KR20240040607A - Efficient Congestion Control for INDUSTRIAL Traffic in 3GPP 5GS - Google Patents

Abstract

One disclosure of this specification provides a method of operating in a terminal. The method includes driving a Mobility Management (MM) back-off timer or a Session Management (SM) back-off timer; When industrial traffic transmission is required, the method may include stopping or ignoring the MM back-off timer or the SM timer and transmitting SM signaling or MM signaling. The SM signaling or MM signaling may include information indicating override or exception of congestion control.

Description

Efficient Congestion Control for INDUSTRIAL Traffic in 3GPP 5G System {Efficient Congestion Control for INDUSTRIAL Traffic in 3GPP 5GS}

This specification relates to mobile communications.

Thanks to the success of LTE (long term evolution)/LTE-Advanced (LTE-A) for 4th generation mobile communications, interest in the next generation, that is, 5th generation (so-called 5G) mobile communications, is increasing, and research is progressing one after another. .

The 5th generation mobile communication, as defined by the International Telecommunication Union (ITU), refers to providing a data transmission speed of up to 20Gbps and an experienced transmission speed of at least 100Mbps anywhere. The official name is ‘IMT-2020’ and the goal is to commercialize it globally in 2020.

5th generation mobile communication supports multiple numerologies or subcarrier spacing (SCS) to support various services. For example, if SCS is 15kHz, it supports wide area in traditional cellular bands, and if SCS is 30kHz/60kHz, it supports dense-urban, lower latency. and a wider carrier bandwidth, and when SCS is 60kHz or higher, it supports a bandwidth greater than 24.25GHz to overcome phase noise.

The NR frequency band is defined as two types of frequency ranges (FR1, FR2). FR1 is 410 MHz - 7125 MHz, and FR2 is 24250 MHz - 52600 MHz, which can mean millimeter wave (mmW).

For convenience of explanation, among the frequency ranges used in the NR system, FR1 may mean "sub 6GHz range", and FR2 may mean "above 6GHz range" and may be called millimeter wave (mmW). .

Frequency Range designation Corresponding frequency range Subcarrier Spacing FR1 450MHz - 6000MHz 15, 30, 60kHz FR2 24250MHz - 52600MHz 60, 120, 240 kHz

As mentioned above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 may include a band of 410 MHz to 7125 MHz, as shown in Table A7 below. That is, FR1 may include a frequency band of 6GHz (or 5850, 5900, 5925 MHz, etc.). For example, the frequency band above 6 GHz (or 5850, 5900, 5925 MHz, etc.) included within FR1 may include an unlicensed band. Unlicensed bands can be used for a variety of purposes, for example, for communications for vehicles (e.g., autonomous driving).

Frequency Range designation Corresponding frequency range Subcarrier Spacing FR1 410MHz - 7125MHz 15, 30, 60kHz FR2 24250MHz - 52600MHz 60, 120, 240 kHz

ITU proposes three major usage scenarios, such as enhanced Mobile BroadBand (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliable and Low Latency Communications (URLLC).

First, URLLC concerns usage scenarios that require high reliability and low latency. For example, services such as autonomous driving, factory automation, and augmented reality require high reliability and low latency (e.g., latency of less than 1 ms). The current 4G (LTE) latency is statistically 21-43ms (best 10%), 33-75ms (median). This is insufficient to support services that require latency of 1ms or less.

Next, the eMBB usage scenario concerns a usage scenario requiring mobile ultra-wideband.

These ultra-broadband high-speed services seem difficult to accommodate by the core network designed for existing LTE/LTE-A.

Therefore, redesign of the core network is urgently required in the so-called 5th generation mobile communication.

1 is a structural diagram of a next-generation mobile communication network.

5GC (5G Core) may include various components, and in Figure 1, some of them include AMF (Access and Mobility Management Function) 41, SMF (Session Management Function) 42, and PCF (Policy Control). Function) (43), UPF (User Plane Function) (44), AF (Application Function) (45), UDM (Unified Data Management) (46), and N3IWF (Non-3GPP InterWorking Function) (49).

The UE 10 is connected to the data network through the UPF 44 through NG-RAN (Next Generation Radio Access Network).

The UE 10 may also receive data services through untrusted non-3rd Generation Partnership Project (3GPP) access, for example, a Wireless Local Area Network (WLAN). To connect the non-3GPP access to the core network, N3IWF 49 may be deployed.

Figure 2 is an example diagram showing the expected structure of next-generation mobile communication from a node perspective.

As can be seen with reference to FIG. 2, the UE is connected to a data network (DN) through a next-generation Radio Access Network (RAN).

The control plane function (CPF) node shown is all or part of the functions of the Mobility Management Entity (MME) of 4th generation mobile communication, and the control plane functions of Serving Gateway (S-GW) and PDN Gateway (P-GW). Perform all or part of The CPF node includes an Access and Mobility Management Function (AMF) and a Session Management Function (SMF).

The illustrated User Plane Function (UPF) node is a type of gateway through which user data is transmitted and received. The UPF node can perform all or part of the user plane functions of S-GW and P-GW of 4th generation mobile communication.

The illustrated PCF (Policy Control Function) is a node that controls the operator's policy.

The illustrated Application Function (AF) is a server for providing various services to the UE.

The illustrated Unified Data Management (UDM) is a type of server that manages subscriber information, like the Home Subscriber Server (HSS) of 4th generation mobile communication. The UDM stores and manages the subscriber information in a Unified Data Repository (UDR).

The depicted Authentication Server Function (AUSF) authenticates and manages the UE.

The network slice selection function (NSSF) shown is a node for network slicing as will be described later.

In Figure 2, a UE can access two data networks simultaneously using multiple PDU (protocol data unit or packet data unit) sessions.

Figure 3 is an example diagram showing an architecture for supporting simultaneous access to two data networks.

Figure 3 shows an architecture for a UE to simultaneously access two data networks using one PDU session.

The reference points shown in Figures 2 and 3 are as follows.

N1 represents a reference point between UE and AMF.

N2 represents a reference point between (R)AN and AMF.

N3 represents a 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 a reference point between UDM and AMF.

N9 represents a reference point between UPFs.

N10 represents a reference point between UDM and SMF.

N11 represents a 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 a reference point between AMFs.

N15 represents the reference point between PCF and AMF.

N16 represents a reference point between SMFs.

N22 represents a reference point between AMF and NSSF.

Figure 4 is another example diagram showing the structure of the Radio Interface Protocol between the UE and gNB.

The wireless interface protocol is based on the 3GPP wireless access network standard. The wireless interface protocol consists of a physical layer, a data link layer, and a network layer horizontally, and a user plane for data information transmission and control vertically. It is divided into a control plane for signaling.

The protocol layers are L1 (layer 1), L2 (layer 2), and L3 (layer 3) based on the lower three layers of the Open System Interconnection (OSI) standard model, which is widely known in communication systems. ) can be divided into

Below, each layer of the wireless protocol is described.

The first layer, the physical layer, provides information transfer service using a physical channel. The physical layer is connected to the upper Medium Access Control layer through a transport channel, and data is transmitted between the medium access control layer and the physical layer through the transport channel. And, data is transmitted between different physical layers, that is, between the physical layers of the transmitting side and the receiving side, through physical channels.

The second layer includes a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, and a Packet Data Convergence Protocol (PDCP) layer.

The third layer includes Radio Resource Control (hereinafter abbreviated as RRC). The RRC layer is defined only in the control plane and is related to the setup, re-configuration, and release of radio bearers (Radio Bearer (abbreviated as RB)), and is related to logical channels, transport channels, and physical channels. Responsible for control. At this time, RB refers to the service provided by the second layer for data transfer between the terminal and E-UTRAN.

The NAS (Non-Access Stratum) layer performs functions such as connection management (session management) and mobility management.

The NAS layer is divided into a NAS entity for MM (Mobility Management) and a NAS entity for SM (session Management).

1) The NAS entity for MM provides the following general functions.

NAS procedures related to AMF, including:

- Registration management and access management procedures. AMF supports the following functions:

- Secure NAS signal connection between UE and AMF (integrity protection, encryption)

2) The NAS entity for SM performs session management between the UE and SMF.

SM signaling messages are processed, i.e. generated and processed, at the NAS-SM layer of the UE and SMF. The content of SM signaling messages is not interpreted by AMF.

- In case of SM signaling transmission,

- The NAS entity for the MM creates a NAS-MM message with a security header indicating NAS transmission of SM signaling and additional information about the receiving NAS-MM to derive how and where to deliver the SM signaling message.

- Upon receiving SM signaling, the NAS entity for SM performs an integrity check of the NAS-MM message and interprets additional information to derive how and where to derive the SM signaling message.

Meanwhile, in FIG. 4, the RRC layer, RLC layer, MAC layer, and PHY layer located below the NAS layer are collectively referred to as an access layer (Access Stratum: AS).

The network system (i.e., 5GC) for next-generation mobile communications (i.e., 5G) also supports non-3GPP access. A representative example of the non-3GPP access is WLAN access. The WLAN access may include both trusted and untrusted WLANs.

In the system for 5G, AMF performs registration management (RM) and connection management (CM) for 3GPP access as well as non-3GPP access.

Meanwhile, in the hyper-connected intelligent information society of the future with the 4th Industrial Revolution and 5G mobile communication, people and objects, online and offline, are organically connected to each other to exchange and process information. Ultra Reliable Low Latency Communications (URLLC) ) Networking technology is emerging as an essential network infrastructure-based technology.

As part of URLLC networking technology, industrial traffic such as time-sensitive networking (TSN) is being introduced.

On the other hand, the explosive increase in users' data usage may cause problems in mobile communication networks becoming congested. Currently, in 3GPP 5GS (5G System), when network congestion occurs in the CN (Core Network), the network rejects the request from the UE (i.e., the terminal) and sets a back-off timer to the UE (i.e., the terminal). to prevent re-requests from being made until the back-off timer expires.

However, in the case of industrial (e.g., TSN or DetNet, TSC, URLLC, IIoT) traffic, the QoS requirements for latency are very strict, so specific industrial (e.g., TSN or DetNet, TSC, URLLC, IIoT) traffic Traffic must be transmitted very quickly and immediately.

Therefore, a situation may arise where industrial (eg, TSN or DetNet, TSC, URLLC, IIoT) traffic must be transmitted quickly even in a congestion situation, but this is currently impossible.

Accordingly, the purpose of the disclosure of this specification is to present a method for solving the above-mentioned problems.

In order to solve the above-described problem, one disclosure of the present specification provides an operating method in a terminal. The method includes driving a Mobility Management (MM) back-off timer or a Session Management (SM) back-off timer; When industrial traffic transmission is required, the method may include stopping or ignoring the MM back-off timer or the SM timer and transmitting SM signaling or MM signaling. The SM signaling or MM signaling may include information indicating override or exception of congestion control.

In order to solve the above-described problem, one disclosure of the present specification provides a chipset installed in a terminal. The chipset includes at least one processor; and may include at least one memory that stores instructions and is operably electrically connectable to the at least one processor. Based on the instruction being executed by the at least one processor, the operations performed include: driving a Mobility Management (MM) back-off timer or a Session Management (SM) back-off timer; When industrial traffic transmission is required, the method may include stopping or ignoring the MM back-off timer or the SM timer and transmitting SM signaling or MM signaling. The SM signaling or MM signaling may include information indicating override or exception of congestion control.

In order to solve the above-described problem, one disclosure of the present specification provides a device for a terminal. The device includes a transmitter and receiver; at least one processor; and may include at least one memory that stores instructions and is operably electrically connectable to the at least one processor. Based on the instruction being executed by the at least one processor, the operations performed include: driving a Mobility Management (MM) back-off timer or a Session Management (SM) back-off timer; When industrial traffic transmission is required, the method may include stopping or ignoring the MM back-off timer or the SM timer and transmitting SM signaling or MM signaling. The SM signaling or MM signaling may include information indicating override or exception of congestion control.

The industrial traffic may be: traffic for Time Sensitive Network (TSN), Time-Sensitive Communication (TSC), Deterministic Networking (DetNet), Ultra Reliable and Low Latency Communications (URLLC), or Industrial Internet of Things (IIoT). .

The disclosure of the present specification provides for urgent or important industrial traffic (e.g., TSN traffic, TSC traffic, DetNet traffic, URLLC traffic) even if the SM Backoff timer or MM Backoff timer is operating depending on the network congestion situation. , or IIoT traffic) can be transmitted normally.

1 is a structural diagram of a next-generation mobile communication network.
Figure 2 is an example diagram showing the expected structure of next-generation mobile communication from a node perspective.
Figure 3 is an example diagram showing an architecture for supporting simultaneous access to two data networks.
Figure 4 is another example diagram showing the structure of the Radio Interface Protocol between the UE and gNB.
5 is a signal flow diagram illustrating an exemplary registration procedure.
6A and 6B are signal flow diagrams illustrating an exemplary PDU session establishment procedure.
Figures 7a and 7b show the modification procedure of a PDU session.
Figures 8a and 8b show a procedure for rejecting a UE's MM operation or SM operation in case of network congestion or overload. Figure 8c shows an example in which an RRC connection is rejected.
Figure 9 is an example diagram showing a network architecture interworking with a TSN network.
Figure 10 is an example diagram showing an architecture supporting time-sensitive communication and time synchronization services.
Figure 11 is an exemplary diagram showing one disclosure of the present specification.
Figure 12 shows a block diagram of a processor on which the disclosure of the present specification is implemented.
13 shows a wireless communication system according to one embodiment.
Figure 14 illustrates a block diagram of a network node according to one embodiment.
Figure 15 is a block diagram showing the configuration of the UE 100 according to an embodiment.
FIG. 16 is a block diagram showing in detail the transceiver unit of the first device shown in FIG. 13 or the transceiver unit of the device shown in FIG. 15.
17 illustrates a communication system 1 to which the disclosure of this specification applies.

It should be noted that the technical terms used in this specification are only used to describe specific embodiments and are not intended to limit the content of this specification. In addition, technical terms used in this specification, unless specifically defined in a different way in this specification, should be interpreted as meanings generally understood by those skilled in the art in the technical field to which the disclosure of this specification pertains. It should not be interpreted in a very comprehensive sense or in an excessively reduced sense. Additionally, if the technical terms used in this specification are incorrect technical terms that do not accurately express the content and idea of the present specification, they should be replaced with technical terms that can be correctly understood by those skilled in the art. Additionally, general terms used in this specification should be interpreted as defined in the dictionary or according to the context, and should not be interpreted in an excessively reduced sense.

Additionally, as used herein, singular expressions include plural expressions, unless the context clearly dictates otherwise. In this application, terms such as constitute or have should not be construed as necessarily including all of the various components or steps described in the specification, and some of the components or steps may not be included. , or it should be interpreted that it may further include additional components or steps.

Additionally, terms including ordinal numbers, such as first, second, etc., used in this specification may be used to describe various components, but the components should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, a first component may be named a second component without departing from the scope of rights, and similarly, the second component may also be named a first component.

When a component is mentioned as being connected or connected to another component, it may be directly connected or connected to the other component, but other components may also exist in between. On the other hand, when it is mentioned that a component is directly connected or directly connected to another component, it should be understood that no other components exist in the middle.

Hereinafter, the embodiment will be described in detail with reference to the attached drawings, but identical or similar components will be assigned the same reference numbers regardless of the reference numerals, and duplicate descriptions thereof will be omitted. Additionally, in explaining the contents of this specification, if it is determined that a detailed description of related known technology may obscure the gist of the present specification, the detailed description will be omitted. In addition, it should be noted that the attached drawings are only intended to facilitate easy understanding of the content and idea of the present specification, and should not be construed as limiting the content and idea of the present specification by the attached drawings. The contents and ideas of this specification should be construed as extending to all changes, equivalents, or substitutes other than the attached drawings.

As used herein, “A or B” may mean “only A,” “only B,” or “both A and B.” In other words, in this specification, “A or B” may be interpreted as “A and/or B (A and/or B).” For example, as used herein, “A, B or C” means “only A”, “only B”, “only C”, or “any and all combinations of A, B and C ( It can mean “any combination of A, B and C)”.

As used herein, a slash (/) or a comma (comma) may mean “and/or (and/or)”. For example, “A/B” means “A and/or B” Accordingly, “A/B” can mean “only A”, “only B”, or “both A and B”. For example, “A, B, C” can mean “A, B, or C”.

As used herein, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” In addition, in this specification, the expression “at least one of A or B” or “at least one of A and/or B” means “at least one It can be interpreted the same as "at least one of A and B".

Additionally, as used herein, “at least one of A, B and C” means “only A”, “only B”, “only C”, or “A, B and C”. It can mean “any combination of A, B and C”. It can also mean “at least one of A, B or C” or “at least one “At least one of A, B and/or C” may mean “at least one of A, B and C.”

Additionally, parentheses used in this specification may mean “for example”. Specifically, when indicated as “control information (PDCCH)”, “PDCCH” is suggested as an example of “control information”. It may have happened. In other words, “control information” in this specification is not limited to “PDCCH”, and “PDDCH” may be proposed as an example of “control information.” Additionally, even when “control information (i.e., PDCCH)” is indicated, “PDCCH” may be proposed as an example of “control information.”

Technical features described individually in one drawing in this specification may be implemented individually or simultaneously.

In the attached drawings, a UE (User Equipment) is shown by way of example, but the illustrated UE may also be referred to by terms such as UE (100) (Terminal), ME (Mobile Equipment), etc. Additionally, the UE may be a portable device such as a laptop, mobile phone, PDA, smart phone, or multimedia device, or it may be a non-portable device such as a PC or vehicle-mounted device.

<Registration Procedure>

The UE needs to obtain authorization to enable mobility tracking and receive data, and to receive services. For this, the UE must register with the network. The registration procedure is performed when the UE needs to make initial registration for the 5G system. Additionally, the registration procedure is performed when the UE performs periodic registration updates, moves to a new tracking area (TA) in idle mode, and when the UE needs to perform periodic registration updates.

During the initial registration procedure, the UE's ID may be obtained from the UE. AMF can forward PEI (IMEISV) to UDM, SMF and PCF.

5A and 5B are signal flow diagrams illustrating an example registration procedure.

1) The UE can transmit an AN message to the RAN. The AN message may include AN parameters and a registration request message. The registration request message may include information such as registration type, subscriber permanent ID or temporary user ID, security parameters, NSSAI, 5G capability of the UE, and PDU session status.

For 5G RAN, the AN parameters may include SUPI or temporary user ID, selected network, and NSSAI.

The registration type can be either “initial registration” (i.e., the UE is in an unregistered state), “mobility registration update” (i.e., the UE is in a registered state and starts the registration procedure due to mobility), or “periodic registration update” "(i.e. the UE is in a registered state and has started the registration procedure due to periodic update timer expiration). If a temporary user ID is included, the temporary user ID indicates the last serving AMF. If the UE has already registered via non-3GPP access in a PLMN different from the PLMN of the 3GPP access, the UE may not provide the UE temporary ID assigned by the AMF during the registration procedure via non-3GPP access.

Security parameters can be used for authentication and integrity protection.

The PDU session state indicates the (previously established) PDU sessions available to the UE.

2) If SUPI is included or the temporary user ID does not indicate a valid AMF, the RAN may select an AMF based on (R)AT and NSSAI.

If (R)AN cannot select an appropriate AMF, it selects a random AMF according to the local policy and forwards the registration request to the selected AMF. If the selected AMF cannot serve the UE, the selected AMF selects another more appropriate AMF for the UE.

3) The RAN transmits an N2 message to the new AMF. The N2 message includes N2 parameters and a registration request. The registration request may include registration type, subscriber permanent identifier or temporary user ID, security parameters, NSSAI and MICO mode preferences, etc.

When 5G-RAN is used, N2 parameters include location information, cell identifier, and RAT type related to the cell where the UE is camping.

If the registration type indicated by the UE is periodic registration update, processes 4 to 17 described later may not be performed.

4) The newly selected AMF may transmit an information request message, such as Namf_Communication_UEContextTransfer, to the previous AMF.

If the UE's temporary user ID is included in the registration request message and the serving AMF has changed since the last registration, the new AMF may send an information request message containing complete registration request information to the old AMF to request the UE's SUPI and MM context. there is.

5) The previous AMF transmits an information response message, such as Namf_Communication_UEContextTransfer response, to the newly selected AMF. The information response message may include SUPI, MM context, and SMF information.

Specifically, the previous AMF sends an information response message containing the UE's SUPI and MM context.

- If there is information about an active PDU session in the previous AMF, the previous AMF may include SMF information including the ID of the SMF and the PDU session ID in the information response message.

6) The new AMF sends an Identity Request message to the UE if SUPI is not provided by the UE or is not retrieved from the previous AMF.

7) The UE transmits an Identity Response message including the SUPI to the new AMF.

8) AMF may decide to trigger AUSF. In this case, AMF may select AUSF based on SUPI.

9) AUSF can initiate authentication of UE and NAS security functions.

10) The new AMF may transmit a Namf_Communication_RegistrationCompleteNotify message to the previous AMF.

11) The new AMF can transmit an Identity Request message to the UE.

If the PEI has not been provided by the UE or has not been retrieved from a previous AMF, an Identity Request message may be sent for the AMF to retrieve the PEI.

12) The new AMF checks the identifier.

13) If process 14 described below is performed, the new AMF selects UDM based on SUPI.

14) The new AMF performs a registration procedure in UDM.

15) The new AMF can select PCF based on SUPI.

16) The new AMF carries out Policy Association Establishment with PCF.

17) The new AMF transmits a PDU Session Update SM Context message or a PDU Session Release SM Context message to the SMF.

18-19) The new SMF transmits an AMF Mobility Request message to N3IWF and receives a Mobility Response message from AMF.

20) The previous AMF transmits a UE Context Termination Request message to the PCF.

If the previous AMF had previously requested that the UE context be established in the PCF, the previous AMF may delete the UE context in the PCF.

21) The new AMF transmits a registration acceptance message to the UE. The registration acceptance message may include temporary user ID, registration area, mobility restrictions, PDU session state, NSSAI, periodic registration update timer, and allowed MICO mode.

When the AMF assigns a new temporary user ID, the temporary user ID may be further included in the registration acceptance message. When mobility restrictions are applied to the UE, information indicating mobility restrictions may be additionally included in the registration accept message. AMF may include information indicating the PDU session state for the UE in the registration accept message. The UE may remove any internal resources associated with the PDU session that are not marked as active in the received PDU session state. If PDU session state information is in the Registration Request, the AMF may include information indicating the PDU session state to the UE in the registration accept message.

22) The UE transmits a registration completion message to the new AMF.

<PDU session establishment procedure>

There may be two types of PDU (Protocol Data Unit) session establishment procedures as follows.

- UE-initiated PDU session establishment procedure

- Network-initiated PDU session establishment procedure. For this purpose, the network may send a device trigger message to the UE's application(s).

6A and 6B are signal flow diagrams illustrating an exemplary PDU session establishment procedure.

The procedures shown in FIGS. 6A and 6B assume that the UE has already registered on the AMF according to the registration procedure shown in FIG. 5. Therefore, it is assumed that AMF has already obtained user subscription data from UDM.

1) UE transmits a NAS message to AMF. The message may include Single Network Slice Selection Assistance Information (S-NSSAI), data network name (DNN), PDU session ID, request type, N1 SM information, etc.

Specifically, the UE includes the S-NSSAI from the allowed NSSAI of the current access type. If information about the mapped NSSAI is provided to the UE, the UE may provide both an S-NSSAI based on the allowed NSSAI and a corresponding S-NSSAI based on information on the mapped NSSAI. Here, the mapped NSSAI information is information that maps each S-NSSAI of the allowed NSSAI to the S-NSSAI of the NSSAI set for HPLMN (Home Public Land Mobile Network).

More specifically, the UE may extract and store information on the allowed S-NSSAI and the mapped S-NSSAI included in the registration acceptance message received from the network (i.e., AMF) in the registration procedure of FIG. 5. there is. Accordingly, the UE may transmit the PDU session establishment request message by including both the S-NSSAI based on the allowed NSSAI and the corresponding S-NSSAI based on information on the mapped NSSAI.

To establish a new PDU session, the UE may create a new PDU session ID.

The UE can start the PDU session establishment procedure initiated by the UE by transmitting a NAS message including a PDU session establishment request message in N1 SM information. The PDU session establishment request message may include request type, SSC mode, and protocol configuration options.

If PDU session establishment is to establish a new PDU session, the request type indicates "initial request". However, if there is an existing PDU session between 3GPP access and non-3GPP access, the request type may indicate “Existing PDU Session”.

The NAS message transmitted by the UE is encapsulated in the N2 message by the AN. The N2 message is transmitted through AMF and may include user location information and access technology type information.

- N1 SM information may include a SM PDU DN request container containing information about PDU session authentication by an external DN.

2) AMF may determine that the message corresponds to a request for a new PDU session if the request type indicates “initial request” and the PDU session ID was not used for the UE's existing PDU session.

If the NAS message does not contain S-NSSAI, AMF may determine the default S-NSSAI for the requested PDU session according to the UE subscription. AMF can store the PDU session ID and SMF ID in association.

The AMF can select SMF.

3) AMF may transmit an Nsmf_PDUSession_CreateSMContext request message or an Nsmf_PDUSession_UpdateSMContext request message to the selected SMF.

The Nsmf_PDUSession_CreateSMContext request message includes SUPI, DNN, S-NSSAI(s), PDU Session ID, AMF ID, Request Type, PCF ID, Priority Access, N1 SM container, User location information, Access Type, PEI, GPSI, UE presence in May include LADN service area, Subscription For PDU Session Status Notification, DNN Selection Mode, and Trace Requirements. The SM container may include a PDU Session Establishment request message.

The Nsmf_PDUSession_UpdateSMContext request message may include SUPI, DNN, S-NSSAI(s), SM Context ID, AMF ID, Request Type, N1 SM container, User location information, Access Type, RAT type, and PEI. The N1 SM container may include a PDU Session Establishment request message.

AMF ID is used to identify the AMF serving the UE. N1 SM information may include a PDU session establishment request message received from the UE.

4) SMF transmits a subscriber data request message to UDM. The subscriber data request message may include a subscriber permanent ID and DNN. UDM may send a subscription data response message to SMF.

In step 3 above, if the request type indicates "existing PDU session", the SMF determines that the request is due to a handover between 3GPP access and non-3GPP access. SMF can identify existing PDU sessions based on the PDU session ID.

If the SMF has not yet retrieved SM-related subscription data for the UE associated with the DNN, the SMF may request subscription data.

Subscription data may include information about the authenticated request type, authenticated SSC mode, and basic QoS profile.

The SMF can verify whether the UE request complies with user subscription and local policies. Alternatively, the SMF rejects the UE request through NAS SM signaling delivered by the AMF (including the relevant SM rejection reason), and the SMF informs the AMF that the PDU session ID should be considered released.

5) SMF sends the Nsmf_PDUSession_CreateSMContext Response message or Nsmf_PDUSession_UpdateSMContext Response message to AMF.

The Nsmf_PDUSession_CreateSMContext Response message may include Cause, SM Context ID, or N1 SM container. The N1 SM container may include PDU Session Reject.

In step 3 above, if the SMF has received the Nsmf_PDUSession_CreateSMContext request message and the SMF can process the PDU Session establishment request message, the SMF SM context is created and the SM context ID is delivered to the AMF.

6) Secondary authentication/authorization is optionally performed.

7a) If an operational PCC is used for a PDU session, the SMF selects the PCF.

7b) The SMF performs the SM policy association establishment procedure to establish SM policy association with the PCF.

8) If the request type in step 3 indicates “initial request”, the SMF selects SSC mode for the PDU session. If step 5 is not performed, SMF may also select UPF. For request type IPv4 or IPv6, SMF can assign an IP address/prefix for the PDU session.

9) SMF performs the SM policy association modification procedure and provides information on policy control request trigger conditions.

10) If the request type indicates "initial request" and the SMF initiates the N4 session establishment procedure using the selected UPF, otherwise it may initiate the N4 session modification procedure using the selected UPF.

10a) SMF sends an N4 session establishment/modification request message to UPF. Additionally, the SMF can provide packet detection, enforcement, and reporting rules to be installed in UPF for PDU sessions. If the SMF is assigned CN tunnel information, the CN tunnel information may be provided to the UPF.

10b) UPF may respond by sending an N4 session establishment/modification response message. If CN tunnel information is allocated by UPF, CN tunnel information may be provided to SMF.

11) The SMF transmits the Namf_Communication_N1N2MessageTransfer message to the AMF. The Namf_Communication_N1N2MessageTransfer message may include PDU Session ID, N2 SM information, and N1 SM container.

The N2 SM information includes PDU Session ID, QFI (QoS Flow ID), QoS Profile(s), CN Tunnel Info, S-NSSAI from the Allowed NSSAI, Session-AMBR, PDU Session Type, User Plane Security Enforcement information, UE Integrity Protection Maximum Data Rate may be included.

The N1 SM container may include a PDU session establishment acceptance message.

The PDU session establishment acceptance message may include permitted QoS rules, SSC mode, S-NSSAI, and assigned IPv4 address.

12) AMF transmits an N2 PDU session request message to the RAN. The message may include N2 SM information and NAS message. The NAS message may include a PDU session ID and a PDU session establishment acceptance message.

AMF may transmit a NAS message including a PDU session ID and a PDU session establishment acceptance message. Additionally, the AMF includes the N2 SM information received from the SMF in the N2 PDU session request message and transmits it to the RAN.

13) RAN may exchange specific signaling with the UE related to information received from the SMF.

RAN also allocates RAN N3 tunnel information for PDU sessions.

RAN delivers the NAS message provided in step 10 to the UE. The NAS message may include PDU session ID and N1 SM information. The N1 SM information may include a PDU session establishment acceptance message.

The RAN transmits the NAS message to the UE only when the necessary RAN resources are configured and allocation of RAN tunnel information is successful.

14) RAN transmits an N2 PDU session response message to AMF. The message may include PDU session ID, cause, and N2 SM information. The N2 SM information may include a PDU session ID, (AN) tunnel information, and a list of allowed/denied QoS profiles.

- RAN tunnel information may correspond to the access network address of the N3 tunnel corresponding to the PDU session.

15) AMF can transmit the Nsmf_PDUSession_UpdateSMContext request message to SMF. The Nsmf_PDUSession_UpdateSMContext request message may include N2 SM information. Here, the AMF may transmit N2 SM information received from the RAN to the SMF.

16a) If the N4 session for the PDU session has not already been established, the SMF may initiate the N4 session establishment procedure with the UPF. Otherwise, SMF can initiate the N4 session modification procedure using UPF. SMF can provide AN tunnel information and CN tunnel information. CN tunnel information may need to be provided only if the SMF selects CN tunnel information in step 8.

16b) The UPF may transmit an N4 session modification response message to the SMF.

17) The SMF transmits the Nsmf_PDUSession_UpdateSMContext Response message to the AMF.

After this process is completed, AMF can deliver related events to SMF.

18) The SMF transmits the Nsmf_PDUSession_SMContextStatusNotify message.

19) SMF transmits information to the UE through UPF. Specifically, in the case of PDU Type IPv6, SMF can create an IPv6 Router Advertisement and transmit it to the UE through N4 and UPF.

20) If PDU session establishment is not successful during the procedure, SMF notifies AMF.

<PDU session modification procedure>

Figures 7a and 7b show the modification procedure of a PDU session.

PDU sessions can be established/managed based on the PDU session modification procedure.

The PDU session modification procedure may be initiated by the UE or by the network.

1a) When initiated by the UE, the UE may initiate the PDU session modification procedure by transmitting a NAS message. The NAS message may include an N1 SM container. The N1 SM container may include a PDU session modification request message, a PDU session ID, and information about the UE's maximum integrity protection data rate. The PDU session modification request message may include a PDU session ID, packet filter, information on requested QoS, 5GSM core network capability, and the number of packet filters. The maximum integrity protection data rate of the UE indicates the maximum data rate at which the UE can support UP integrity protection. The number of packet filters indicates the number of packet filters supported for QoS rules.

The NAS message is transmitted through the RAN to an appropriate AMF according to the location information of the UE. Then, the AMF transmits the Nsmf_PDUSession_UpdateSMContext message to the SMF. The message may include a session management (SM) context ID and an N1 SM container. The N1 SM container may include a PDU session modification request message.

1b) When initiated by a PCF among network nodes, the PCF can notify the SMF of policy changes by initiating the SM policy association modification procedure.

1c) When initiated by a UDM among network nodes, the UDM can update the subscription data of the SMF by sending a Nudm_SDM_Notification message. The SMF may update session management subscriber data and deliver an ACK message to the UDM.

1d) If initiated by an SMF among network nodes, the SMF may trigger a QoS update.

When triggered according to 1a to 1d above, the SMF may perform a PDU session modification procedure.

1e) When initiated by an AN among network nodes, the AN can notify the SMF when AN resources to which a QoS flow is mapped are released. The AN can transmit the N2 message to AMF. The N2 message may include PDU session ID and N2 SM information. The N2 SM information may include QFI (QoS flow ID), user location information, and an indication that the QoS flow is released. The AMF may transmit the Nsmf_PDUSession_UpdateSMContext message. The message may include SM context ID and N2 SM information.

2) The SMF can transmit a report on the subscription event by performing the SM policy affiliation modification procedure. If the PDU session modification procedure is triggered by 1b or 1d, this step can be skipped. If a dynamic PCC is not deployed in the network, the SMF can apply internal policies to determine changes to the QoS profile.

Processes 3 to 7, described later, may not be performed if PDU session modification requires only UPF operation.

3a) When initiated by the UE or AN, the SMF may respond to the AMF by sending a Nsmf_PDUSession_UpdateSMContext message. The message may include N2 SM information and N2 SM container. The N2 SM information may include PDU session ID, QFI, QoS profile, and session-AMBR. The N1 SM container may include a PDU session modification command. The PDU session modification command may include a PDU session ID, QoS rule, QuS rule operation, QoS flow unit QoS parameter, and session-AMBR.

The N2 SM information may include information that AMF should transmit to AN. The N2 SM information may include QFI and QoS profile to notify the AN that one or more QoS flows are added or modified. If PDU session modification is requested by a UE for which user plane resources are not configured, the N2 SM information to be delivered to the AN may include information about establishment of user plane resources.

The N1 SM container may include a PDU session modification command to be delivered by the AMF to the UE. The PDU session modification command may include QoS rules and QoS flow unit (level) QoS parameters.

3b) If initiated by the SMF, the SMF may transmit the Namf_Communication_N1N2MessageTransfer message. The message may include N2 SM information and N1 SM container. The N2 SM information may include PDU session ID, QFI, QoS profile, and session-AMBR. The N1 SM container may include a PDU session modification command. The PDU session modification command may include a PDU session ID, QoS rules, and QoS flow unit (level) QoS parameters.

If the UE is in the CM-IDLE state and ATC is activated, the AMF may update and store the UE context based on the Namf_Communication_N1N2MessageTransfer message and then skip steps 3 to 7, which will be described later. When the UE enters a reachable state, that is, the UE enters the CM-CONNECTED state, the AMF may transmit an N1 message to synchronize the UE and the UE context.

4) The AMF may transmit an N2 PDU session request message to AN. The N2 PDU session request message may include N2 SM information received from SMF and a NAS message. The NAS message may include a PDU session ID and N1 SM container. The N1 SM container may include a PDU session modification command.

5) The AN performs AN signaling exchange with the UE related to the information received from the SMF. For example, in the case of NG-RAN, an RRC connection reconfiguration procedure with the UE may be performed to modify the required AN resources related to the PDU session.

6) The AN transmits an N2 PDU session ACK message in response to the received N2 PDU session request. The N2 PDU session ACK message may include N2 SM information and user location information. The N2 SM information may include a list of accepted/rejected QFIs, AN tunnel information, and PDU session ID.

7) The AMF transmits the N2 SM information and user location information received from AN to the SMF through the Nsmf_PDUSession_UpdateSMContext message. Then, the SMF delivers the Nsmf_PDUSession_UpdateSMContext message to the AMF.

8) The SMF transmits an N4 session modification request message to the UPF to update the N4 session of the UPF included in the PDU session modification.

When a new QoS flow is created, the SMF updates the UL packet detection rule of the new QoS flow together with the UPF.

9) The UE transmits a NAS message in response to receiving a PDU session modification command. The NAS message may include a PDU session ID and N1 SM container. The N1 SM container may include a PDU session modification command ACK.

10) The AN transmits the NAS message to the AMF.

11) The AMF can transmit the N1 SM container and user location information received from the AN to the SMF through the Nsmf_PDUSession_UpdateSMContext message. The N1 SM container may include a PDU session modification command ACK. The SMF may transmit the Nsmf_PDUSession_UpdateSMContext response message to the AMF.

12) The SMF transmits an N4 session modification request message to the UPF in order to update the N4 session of the UPF included in the PDU session modification. The message may include an N4 session ID.

13) When the SMF interacts with the PCF in process 1b or process 2 above, the SMF can inform the PCF whether the PCC decision can be performed or not through the SM policy alliance modification procedure.

The SMF may notify the requesting entity of user location information related to the PDU session change.

<Unified access control>

How to control access to the network

A large number of user equipment (UE) can be connected to a communication system, and various services may exist in the UE. If there are data communication requests from numerous UEs and numerous services, but the network cannot accept data communication requests from all UEs and services, the network needs to increase system stability by controlling connection requests from UEs. If not, problems may occur in which communication access requests such as emergency calls are not processed properly.

This access control method is generally called access control, and the “Unified access control” technique is used in 5G.

Hereinafter, integrated access control will be described in detail.

Depending on operator policy, deployment scenario, subscriber profile, and available services, different criteria are used to determine which access attempts should be allowed or blocked when congestion occurs in 5G systems. . Different criteria for access control are associated with access identity and access category. 5G systems provide a single, unified access control where operators control access based on these two aspects.

In integrated access control, each access attempt is classified with one or more access identifiers and one access category. The UE tests whether the actual access attempt can be performed based on the access identifier associated/matched with the access attempt and the access control information applicable to the access category.

Unified access control supports extensibility to allow for additional standardized access identifiers and access categories, and can be customized based on the operator's own criteria (access identifiers, subscription information, access categories, e.g. network slicing, application and application servers) to support flexibility in allowing operator-defined access identifiers and access categories.

Additionally, the use of Legacy Access Classes 11-15 is expanded when potentially allowing an access attempt to succeed, otherwise the access attempt may be blocked based on user type.

Depending on the operator policy, the 5G system must be able to prevent the UE from accessing the network using barring parameters according to the access identifier and access category. The access identifier is set in the UE as listed in Table 1 below. The access category is defined by combining the conditions for the UE and the access attempt type listed in Table 2 below. One or more access identifiers and one access category are selected and tested for access attempts.

The 5G network may transmit barring control information (i.e., a list of barring parameters associated with an access identifier and access category) within one or more areas in the RAN.

The UE may determine whether a new specific access attempt can be allowed based on the blocking parameters received from the blocking control information and the UE's settings.

In the case of multiple core networks sharing the same RAN, the RAN can apply access control individually for different core networks.

The integrated access control framework can be applied to both UEs accessing the 5G Core Network (CN) using E-UTRA and UEs accessing the 5G CN using New Radio (NR).

The integrated access control framework can be applied to UEs in RRC Idle, RRC Inactive, or RRC Connected states when starting a new access attempt (i.e., a new session request).

5G systems support operator-defined access categories that operators can define as mutually exclusive.

The integrated access control framework can be applied to roamers coming into the PLMN. The serving PLMN may provide the UE with definitions of operator-defined access categories.

Table 3 below illustrates access identifiers.

access identifier number UE settings 0 The UE does not set any parameters from this table. One The UE is configured for multimedia priority service (MPS). 2 US is set up for essential (mission critical) services (MCS: mission critical service). 3 Applies to disaster conditions 4-10 Reservation for secondary use 11 Access class 11 is set within the UE. 12 Access class 12 is set within the UE. 13 Access class 13 is set within the UE. 14 Access class 14 is set within the UE. 15 Access class 15 is set within the UE.

The access identifier can be blocked at any time.

Access　Category number Conditions related to UE
(Conditions related to UE) Type of access attempt
(Type of access attempt) 0 All MO signaling resulting from paging One The UE is configured for delay tolerant service and may be the subject of access control for access category 1 (object of access control determined according to the relationship between the UE's HPLMN and the selected PLMN). All except for Emergency 2 All Emergency 3 All except conditions of access category 1 NAS level MO signaling resulting from non-paging 4 All except conditions of access category 1 MMTEL(multimedia telephony) voice (NOTE 3) 5 All except conditions of access category 1 MMTEL video 6 All except conditions of access category 1 sms 7 All except conditions of access category 1 MO data that does not belong to other access categories (NOTE 4) 8 All except conditions of access category 1 RRC level MO signaling due to consequences other than paging 9-31 Reserved standardized　Access　Categories 32-63 All Can be set based on business classification

The 5G network may broadcast barring control information in one or more areas of the RAN. Blocking control information may be, for example, a list of blocking parameters related to an access identifier (ID) and access category. The UE may determine whether a particular new access attempt is permitted based on the blocking parameters (which the UE receives from broadcasted blocking control information) and the UE's settings.

In the case of multiple core networks sharing the same RAN, the RAN can apply access control individually for different core networks.

The integrated access control framework may be applicable for both UEs accessing the 5G Core Network (CN) using E-UTRA and UEs accessing the 5G CN using NR.

The integrated access control framework may be applicable to UEs in the Radio Resource Control (RRC) Idle state, RRC Inactive state, and RRC Connected state when the UE initiates a new access attempt (e.g., a new session request).

For reference, “new session request” in RRC Connected state may mean an event. For example, events include new MMTEL voice sessions, MMTEL video sessions, sending SMS (SMS over IP, or SMS over NAS), establishing new PDU sessions, modifying existing PDU sessions, and user plane updates for existing PDU sessions. It may be a service request to re-establish.

5G systems may support a means for operators to define operator-defined access categories as mutually exclusive. For example, examples of criteria for provider-defined access categories could be network slicing, applications, and application servers.

The integrated access control framework may be applicable to inbound roamers to the PLMN.

The serving PLMN may provide definitions of operator-defined access categories to the UE.

If the UE needs to access the 5G System (5GS), the UE may first perform an access control check to determine whether access is permitted. Access control checks can be performed on access attempts defined by a list of events, such as:

a) When the UE is in 5GMM (5GS Mobility Management)-IDLE mode through 3GPP access, and an event occurs requiring transition to 5GMM-CONNECTED mode; and

b) If the UE is in 5GMM-CONNECTED mode with 3GPP access, or is in 5GMM-CONNECTED mode with RRC inactive indication, and one of the following events occurs:

b-1) The NAS layer (e.g. 5GMM) of the UE receives MO-MMTEL-voice-call-started information/indication, MO-MMTEL-video-call-started from the upper layer (e.g. application layer) When you receive information/indications or MO-SMSoIP-attempt-started information/indications;

b-2) The NAS layer (e.g., 5GMM) of the UE receives a request to transmit a mobile originated SMS over NAS from the upper layer (e.g., application layer), and the request causes the UE to operate in 5GMM-IDLE mode. If it does not trigger a service request to switch to 5GMM-CONNECTED mode;

b-3) The NAS layer (e.g. 5GMM) of the UE receives a request from a higher layer (e.g. application layer) to transmit a UL NAS TRANASPORT message for the purpose of establishing a PDU session, and the request causes the UE to 5GMM- If it does not trigger a service request to switch from IDLE mode to 5GMM-CONNECTED mode;

b-4) The NAS layer (e.g. 5GMM) of the UE receives a request from a higher layer (e.g. application layer) to transmit a UL NAS TRANASPORT message for the purpose of PDU session modification, and the request causes the UE to 5GMM- If it does not trigger a service request to switch from IDLE mode to 5GMM-CONNECTED mode;

b-5) When the NAS layer (e.g., 5GMM) of the UE receives a request to re-establish user-plane resources for an existing PDU session; and

b-6) When the UE's NAS layer (e.g. 5GMM) is notified that an uplink user data packet will be transmitted for a PDU session with user-plane resources suspended.

When the NAS layer of the UE detects one of the above-described events, the NAS layer of the UE may perform an operation of mapping the type of request to one or more access IDs and access categories. And, the lower layer of the UE (e.g., RRC layer) may perform an access barring check on the request based on the determined access ID and access category. For reference, the NAS layer of the UE may recognize the above-described events through information/indications provided from the upper layer and/or when determining the need to initiate normal NAS operation.

To determine the access ID and access category of the request, the UE's NAS layer configures the UE's information, including the reason for access, the type of service requested, and the UE settings for the set of access IDs and access categories. You can check the profile. Here, examples of the set of access IDs and sets of access categories are as follows:

- a set of standardized access IDs;

- a set of standardized access categories; and

- If available, a set of operator-defined access categories.

If the UE needs to initiate an access attempt for one of the events such as examples a) to b-6) above, the UE determines one or more access IDs associated with the access attempt from a set of standardized access IDs. And, one access category related to the access attempt may be determined from among the set of standardized access categories and the set of provider-defined access categories.

For example, the set of access IDs applicable to a request related to an access attempt may be determined by the UE in the following way:

i) In the example of Table 3, for each of access IDs 1, 2, 11, 12, 13, 14 and 15, the UE will check whether the access ID is available in the selected PLMN when a new PLMN is selected. You can. Alternatively, the UE may check whether the access ID is applicable to the RPLMN or equivalent PLMN; and

ii) If there is no available access ID among the access IDs 1, 2, 11, 12, 13, 14 and 15, access ID 0 can be used.

To determine the available access categories for an access attempt, the UE's NAS layer may check rules such as the examples in Table 5 below and use the matching access categories for a barring check.

Table 5 below is an example of the rules used when the UE's NAS layer determines the available access categories for an access attempt.

rule # Type of access attempt Requirements to be satisfied Access Category One Response to paging or NOTIFICATION over non-3GPP access;
5GMM connection management procedure initiated for the purpose of transporting an LPP or location event report message without an ongoing 5GC-MO-LR procedure;
Access attempt to handover of ongoing MMTEL voice call, MMTEL video call or SMSoIP from non-3GPP access Access attempt is for MT access, or handover of ongoing MMTEL voice call, MMTEL video call or SMSoIP from non-3GPP access
0 (=MT_acc) 2 Emergency UE is attempting access for an emergency session 2 (= emergency) 3 Access attempt for operator-defined access category UE stores operator-defined access category definitions valid in the current PLMN, and access attempt is matching criteria of an operator-defined access category definition 32-63
(= based on operator classification) 3.1 Access attempt for MO exception data UE is in NB-N1 mode and allowed to use exception data reporting, and access attempt is for MO data or for MO signaling initiated upon receiving a request from upper layers to transmit user data related to an exceptional event. 10 (= MO exception data) 4 Access attempt for delay tolerant service (a) UE is configured for NAS signaling low priority or UE supporting S1 mode is configured for EAB where "EAB override" does not apply, and(b): the UE received one of the categories a, b or c as part of the parameters for unified access control in the broadcast system information, and the UE is a member of the broadcasted category in the selected PLMN or RPLMN/equivalent PLMN 1 (= delay tolerant) 4.1 MO IMS registration related signaling Access attempt is for MO IMS registration related signaling (eg IMS initial registration, re-registration, subscription refresh)
or for NAS signaling connection recovery during ongoing procedure for MO IMS registration related signaling 9 (= MO IMS registration related signaling) 5 MO MMTel voice call Access attempt is for MO MMTel voice call
or for NAS signaling connection recovery during ongoing MO MMTel voice call 4 (= MO MMTel voice)
6 MO MMTel video call Access attempt is for MO MMTel video callor for NAS signaling connection recovery during ongoing MO MMTel video call 5 (= MO MMTel video)
7 MO SMS over NAS or MO SMSoIP Access attempt is for MO SMS over NAS or MO SMS over SMSoIP transfer or for NAS signaling connection recovery during ongoing MO SMS or SMSoIP transfer 6 (= MO SMS and SMSoIP)
8 UE NAS initiated 5GMM specific procedures Access attempt is for MO signaling 3 (= MO_sig) 8.1 Mobile originated location request Access attempt is for mobile originated location request 3 (= MO_sig) 8.2 Mobile originated signaling transaction towards the PCF Access attempt is for mobile originated signaling transaction towards the PCF 3 (= MO_sig) 9 UE NAS initiated 5GMM connection management procedure or 5GMM NAS transport procedure Access attempt is for MO data 7 (= MO_data) 10 An uplink user data packet is to be sent for a PDU session with suspended user-plane resources No further requirement is to be met 7 (= MO_data)

If an access attempt matches one or more rules, the access category with the lowest rule number among the one or more rules may be selected. If the access attempt matches more than one operator-defined access category definition, the UE may select the operator-defined access category definition with the lowest precedence value. Here, a case where one access attempt matches one or more rules may include a case where multiple events simultaneously trigger one access attempt.

<Congestion control by network>

When congestion occurs, nodes in the core network (eg, AMF) perform NAS level congestion control to avoid or control signaling congestion and DNN congestion.

Generally, when the core network performs congestion control at the NAS level, a delay timer (back-off timer) value is set to the UE in idle mode or connected mode. It is transmitted in the NAS reject message, and the UE does not transmit the request message to the network until the delay timer (back-off timer) expires. The request message may include a Registration Request Message, a Service Request Message, a PDU Session Establishment Request Message, and a PDU Session Modification Request Message.

These back-off timers can be divided into Mobility Management (MM) back-off timers and Session Management (SM) back-off timers.

On the other hand, gNB (i.e., base station) may also perform congestion control. In a RAN or core network congestion situation, the UE may receive a rejection response from the gNB (i.e., base station) along with a wait timer when performing the RRC connection establishment procedure. In this case, the UE cannot initiate the RRC connection establishment procedure until the wait timer received from the gNB (i.e. base station) expires.

Figures 8a and 8b show a procedure for rejecting a UE's MM operation or SM operation in case of network congestion or overload.

As can be seen with reference to FIG. 8A, in the event of network congestion or overload, the UE 100 sends a Registration Request message, a Service Request message, and a Registration Request message through the gNB 200. When a PDU session establishment request message or a PDU session modification request message is transmitted, a node in the network, such as AMF or SMF, transmits a Reject message to the message depending on network conditions such as operator policy. do.

In addition, the AMF or SMF transmits a rejection message and includes a back-off timer in the rejection message so that the UE 100 does not retry the connection until the period expires. .

Or, as shown in FIG. 8B, when network congestion or overload occurs, a node in the network, such as AMF or SMF, provides back-off delay depending on network conditions such as operator policy. The timer may be delivered to the UE 100 through the gNB 200. The back-off timer may be included when transmitting a message from the AMF or SMF to the UE 100.

Meanwhile, gNB 200 may also perform congestion control. For example, in response to an RRC connection request, gNB 200 may perform congestion control by operating as shown in FIG. 8C.

Figure 8c shows an example in which an RRC connection is rejected.

As can be seen with reference to FIG. 8C, when the UE 100 in the idle state wishes to establish an RRC connection to attempt data transmission, it sends an RRC Setup request message to the gNB 200. ) and send it to

At this time, if the gNB (200) is in an overloaded state, the gNB (200) transmits an RRC Reject message to the UE (100). The RRC rejection message may include a wait timer. Then, the UE 100 cannot transmit the RRC setup request message again until the waiting timer expires.

<Contents of related standard documents>

A. NAS level congestion control

NAS level congestion control can be applied generally (i.e., for all NAS messages), per DNN, per S-NSSAI, per DNN and S-NSSAI, or to specific UE groups.

NAS level congestion control is achieved by providing backoff time to the UE. To prevent a large number of UEs from starting requests (almost) simultaneously, 5GC must select each back-off time value so that numerous requests are not delivered simultaneously. Once the UE receives the backoff time, the backoff timer expires, or the UE receives an incoming (Mobile terminated) request from the network, or the UE starts transmitting signaling for emergency services or high priority access. Until this happens, the UE cannot transmit any NAS signaling for the applied congestion control.

AMF and SMF can apply NAS-level congestion control, but must not apply NAS-level congestion control to procedures that are not subject to congestion control.

A-1. Typical NAS-level congestion control

The following description applies to NAS Mobility Management congestion control.

Under normal overload conditions, AMF may reject NAS messages from UEs using 5G-AN. When the NAS request is rejected, the mobility management backoff time may be sent to the UE by AMF. While the Mobility Management (MM) backoff timer is running, the UE can perform deregistration procedures and procedures not subject to congestion control (e.g. high priority access, emergency services), and terminating (Mobile Terminated, MT) services. Except for non-targeted procedures, NAS requests cannot be initiated. Even after the deregistration procedure, the backoff timer may continue to run. While the mobility management (MM) backoff timer is running, the UE may perform a mobility registration update if the UE is already in the CM-CONNECTED state. If the UE receives a paging request or NAS notification message from AMF while the mobility management (MM) backoff timer is running, the UE stops the mobility management (MM) backoff timer and uses the available 3GPP access or non-3GPP access. You must initiate the Service Request procedure or Mobility Registration Update procedure through . When the back-off timer is stopped, if the UE is in CM-IDLE state on non-3GPP access, as soon as it transitions back to CM-CONNECTED state, the UE may need to immediately initiate a UE triggered service request procedure.

To enable the UE to report PS Data Off status changes in the PDU session modification request message, the UE may operate as follows while the NAS MM backoff timer is running in the UE.

- If the UE is in the CM-IDLE state and has not moved out of the registration area, the UE may transmit a Service Request message with an indication that the message is exempt from NAS congestion control. When the UE is in CM-IDLE mode and moves out of the registration area, the UE may send a Mobility Registration Update Request (Mobility Registration Request) message with a follow-up request. The mobility registration update request message may include an indication that it is exempt from NAS congestion control.

- When the UE is in the CM-CONNECTED state, the UE transmits a PDU session modification request including a PS Data Off status change in a UL NAS Transport message containing an indication that it is exempt from NAS congestion control.

When NAS MM congestion control is enabled in AMF, if the UE indicates that the NAS MM message is exempt from NAS congestion control, the AMF will not reject the NAS MM message, and an indication that the NAS SM message is exempt from NAS congestion control Along with this, the NAS SM message is delivered to SMF. SMF then ensures that NAS SM messages are not subject to congestion control. However, without the indication, the SMF may reject the message. Additionally, the SMF may reject the PDU session modification request message if the received PDU session modification request message is not for data off status reporting.

Mobility management backoff timer may not affect cell/RAT/access type and PLMN changes. Changing Cell/RAT/TA/Access Type does not cause the Mobility Management (MM) backoff timer to stop. The mobility management (MM) backoff timer should not be a trigger for PLMN reselection. The backoff timer may be stopped when accessing a new PLMN that is not an equivalent PLMN.

To avoid a large number of UEs transmitting requests simultaneously, AMF must select an MM backoff timer value so that numerous requests are not transmitted simultaneously.

If the UE needs to report an indication that a 5GSM core network capability has changed or an Always-on PDU session is requested while the NAS MM congestion control timer is running and MM signaling cannot be started, the UE must report MM congestion Related MM signaling must be postponed until control is completed, and only after the timer expires can reporting be performed.

For a UE with a scheduled communication pattern, the AMF may consider the UE's communication pattern while selecting a value for the MM backoff timer so that the UE does not miss its only scheduled communication window.

AMF must not reject a registration request message for mobility registration update performed when the UE is already in the CM-CONNECTED state.

AMF can transmit the MM backoff time while rejecting the service request message and UL NAS Transfer message when the UE is already in the CM-CONNECTED state. While the UE is running the MM backoff timer, if it receives a DL NAS Transfer message from AMF, the UE can stop the MM backoff timer.

In the case of CM-IDLE state mobility, the AMF may transmit a registration rejection message including the MM backoff time value to reject the registration request message for mobility registration update.

If the UE registers with the same PLMN for 3GPP access and non-3GPP access and receives the MM back-off time from AMF, the backoff time (and its start and stop) is the same for both 3GPP access and non-3GPP access. It can be applied. On the other hand, if the UE registers with different PLMNs for 3GPP access and non-3GPP access and receives the MM back-off time, the back-off time may be applied only to the PLMN that provides the time to the UE.

If the AMF rejects a registration request message or service request and attempts to deliver an MM backoff time greater than the sum of the UE's periodic registration update timer and implicit deregistration timer, the AMF will To avoid implicitly deregistering the UE, the AMF should adjust the mobile reachability timer and/or the implicit deregistration timer.

A-2. DNN-based congestion control

DNN-based congestion control is designed to relieve NAS SM signaling congestion for UEs using backoff timers that may or may not be associated with DNN, regardless of the presence of S-NSSAI. Both UE and 5GC must support DNN-based congestion control.

Except for messages sent for the purpose of reporting a 3GPP PS Data Off status change for a specific DNN for which the backoff timer is running, the SMF rejects the PDU Session Establishment Request message or PDU Session Modification Request message, DNN-based congestion control can be applied to. The SMF can release a PDU session belonging to a congested DNN by sending a PDU session release command message to the UE along with the DNN backoff timer. If the DNN backoff time is set in the PDU session release command message, the cause value for "reactivation request" may not be set.

Once NWDAF is deployed, the SMF can use the session management congestion control empirical analysis provided by NWDAF to determine the backoff timer provided to the UE.

If DNN-based congestion control is enabled in AMF, for example by setting by OAM, AMF may respond with a NAS Transport Error message to a NAS Transport message containing an SM message. The NAS Transport Error message may include a DNN backoff timer.

The UE may associate the received backoff time with the DNN (i.e., no DNN, only DNN) included in the uplink NAS MM message including the corresponding NAS SM Request message.

If the DNN associated with the backoff timer is not the LADN DNN, the UE may associate the received backoff time with the DNN of the PLMN.

The UE behaves as follows when the DNN backoff timer is running:

- If the DNN is associated with a backoff timer, the UE may not initiate session management procedures for the congested DNN. Instead, the UE can initiate session management procedures for other DNNs. When the UE moves to the 4G network EPS, the UE may not start the session management procedure for the corresponding APN. Instead, when the UE moves to the 4G network EPS, the UE can initiate a session management procedure for a different APN.

- If there is no DNN associated with the backoff timer, the UE can only initiate session management requests for all PDU session types for a specific DNN.

- In case of cell/TA/PLMN/RAT change, untrusted non-3GPP access network change or access type change, the UE may not stop the backoff timer.

- The UE may initiate session management procedures for high priority access and emergency services.

- The UE may initiate a session management procedure to report the data off state change to the network.

- If the UE receives a network initiated session management message other than a PDU session release command for a congested DNN associated with a running backoff timer, the UE may stop the backoff timer and respond with 5GC.

- When the UE receives a PDU session release command message for a congested DNN, it can stop the backoff timer unless it receives a new backoff time from the SMF.

- The UE may be allowed to initiate the PDU session release procedure (i.e. send a PDU session release request message). The UE may not stop the backoff timer when the associated PDU session is released.

When the UE initiates one of the session management procedures exempt from NAS congestion control, the UE indicates that the NAS SM message included within the UL NAS Transport message is exempt from NAS congestion control. When DNN-based congestion control is enabled in AMF and the UE indicates that the NAS SM message contained within the UL NAS Transport message is exempt from NAS congestion control, AMF does not apply DNN-based congestion control to the UL NAS Transport message and does the following: Should be. The AMF forwards the message to the SMF with an indication that the NAS SM message was received with an exemption indication. SMF determines whether NAS SM messages are allowed to be exempt from DNN-based congestion control. If exemption from NAS congestion control is not allowed, SMF rejects the above message. The SMF may refuse to modify a received PDU session if it is not for data off status reporting.

The UE must maintain a separate backoff timer for each DNN that the UE can use.

To prevent a large number of UEs from transmitting requests simultaneously, 5GC can select a backoff timer value so that requests are not transmitted simultaneously.

If the UE needs to report a 5GSM Core Network Capability change or an Always-on PDU session request indication while DNN-based congestion control is running and in cases where SM signaling cannot be initiated, the UE needs to use DNN-based congestion control. Transmission of related SM signaling is postponed until the timer expires, and SM signaling can be transmitted only after the timer expires.

DNN-based SM congestion control is applicable to NAS SM signaling initiated from the UE in the control plane. Session management congestion control does not prevent the UE from transmitting or receiving data or initiating a service request procedure to activate user plane connections to the DNN(s) under session management congestion control.

A-3. S-NSSAI based congestion control

S-NSSAI-based congestion control is used to prevent NAS signaling congestion for the UE by using a backoff timer that may or may not be associated with S-NSSAI, regardless of the presence of a DNN.

The UE must determine the S-NSSAI and DNN (i.e., no S-NSSAI and DNN, no S-NSSAI, S-NSSAI only, S-NSSAI and DNN) and the received backoff time.

S-NSSAI-based congestion control operates as follows.

- If the S-NSSAI is determined to be congested, the SMF applies S-NSSAI-based congestion control to the UE for SM requests, except those sent for the purpose of reporting 3GPP PS Data Off status changes for a specific S-NSSAI. can do. For this purpose, SMF can provide backoff time and HPLMN congestion indication.

- If the UE receives an S-NSSAI based backoff time without an indication of HPLMN congestion, the UE may apply the S-NSSAI backoff timer only in the PLMN from which it received the backoff time. If the UE receives an S-NSSAI-based backoff time with an HPLMN congestion indication, the UE may apply an S-NSSAI-based backoff timer in the PLMN from which it received the backoff time and in other PLMNs.

- The SMF sends a PDU session release request message to the UE containing a back-off timer associated with S-NSSAI only (i.e. without a specific DNN) or a combination of S-NSSAI and a specific DNN, so that the SMF can The belonging PDU session can be released. If NWDAF is deployed, the SMF may use the session management congestion control empirical analysis provided by NWDAF to determine the backoff timer provided to the UE.

- If S-NSSAI based congestion control in AMF is activated, e.g. by setting by OAM, and if S-NSSAI is determined to be congested, AMF may apply S-NSSAI based congestion control for UE initiated session management requests. . In this case, the AMF may transmit a NAS Transport Error message in response to the NAS Transport message including the SM message. The NAS Transport Error message may include a backoff timer. Once NWDAF is deployed, AMF may determine that S-NSSAI is congested based on network slice load level analysis.

- The UE may operate as follows in a PLMN where S-NSSAI-based congestion control is applied when the backoff timer is running.

- If the backoff timer is only associated with S-NSSAI (i.e., not associated with S-NSSAI and DNN), the UE may not start the session management procedure for the congested S-NSSAI.

- If the backoff timer is related to S-NSSAI and DNN, the UE may not start the session management procedure for that combination of S-NSSAI and DNN.

- If the UE receives a network initiated session management message other than a PDU session release command for congested S-NSSAI, the UE may stop this backoff timer and respond with 5GC.

- When the UE receives a PDU session release command message for a congested S-NSSAI, it must stop the backoff timer unless it receives a new backoff time from the SMF.

- In case of cell/TA/PLMN/RAT change, untrusted non-3GPP access network change or access type change, UE may not stop the backoff timer for S-NSSAI or combination of S-NSSAI and DNN .

- The UE may initiate session management procedures for high priority access to S-NSSAI and emergency services.

- The UE may initiate a session management procedure to report a PS Data Off status change for S-NSSAI or a combination of S-NSSAI and DNN.

- If the backoff timer is not associated with an S-NSSAI, the UE can only initiate session management procedures for a specific S-NSSAI.

- If the backoff timer is not associated with S-NSSAI and DNN, the UE can initiate session management procedures only for specific S-NSSAI and DNN.

- The UE is allowed to initiate the PDU session release procedure (e.g. sending a PDU session release request message). The UE may not stop the backoff timer when the associated PDU session is released.

The UE may maintain a separate backoff timer for each S-NSSAI and each combination of S-NSSAI and DNN that the UE can use. When the UE initiates one of the session management procedures exempt from NAS congestion control, the UE indicates that the NAS SM message included within the UL NAS Transport message is exempt from NAS congestion control. When S-NSSAI-based congestion control is enabled in AMF, if the UE indicates that the NAS SM message in the UL NAS Transport message is exempt from NAS congestion control, AMF will not apply S-NSSAI-based congestion control for the UL NAS Transport message. No. The AMF may transmit the NAS SM message and an indication that it has been received along with the exemption indication to the corresponding SMF. The SMF determines whether NAS SM messages are allowed to be exempt from S-NSSAI based congestion control. If exemption of the NAS SM message is not allowed for S-NSSAI-based congestion control, the SMF may reject the message. The SMF may refuse to modify a received PDU session if it is not for data off status reporting.

The backoff timer associated with S-NSSAI or a combination of S-NSSAI and DNN can only be applied for congestion control for session management procedures when the UE is in 5GS.

To avoid a large number of UEs transmitting requests simultaneously, 5GC must select a backoff timer value for S-NSSAI-based congestion control to prevent numerous requests from being transmitted simultaneously.

S-NSSAI based congestion control may allow the UE to initiate a service request procedure to send and receive data or activate a user plane connection for a PDU session associated with the S-NSSAI under congestion control.

A-4. Group-specific NAS-level congestion control

Group-specific NAS level congestion control can be applied to specific UE groups. Group-specific NAS-level congestion control is performed only in 5GC and can be transparent to the UE. AMF or SMF or both may apply NAS level congestion control for UEs associated with the internal group identifier.

< Excerpt from 3GPP TS 24.501 v17.6.1 >

B. Processing of NAS-level mobility management congestion control

AMF can detect 5GMM signaling congestion and perform general NAS level congestion control. In a 5GMM signaling congestion situation, AMF may reject the 5GMM signaling request from the UE. AMF must not refuse:

a) Request for emergency service

b) Request for emergency service fallback;

c) Requests from UEs set to high priority access in the selected PLMN;

d) DEREGISTRATION REQUEST message;

e) A request for MT service triggered by a paging procedure or notification procedure; and

f) If emergency services are directed at a lower tier, a request for initial registration or mobility registration or a request for periodic registration renewal.

If general NAS level congestion control is enabled, AMF may include a value for the MM backoff timer (T3346) in the reject message. The UE starts timer T3346 with the value received in the 5GMM reject message. To prevent a large number of UEs from transmitting requests simultaneously, AMF may determine the value of timer T3346 for the UE.

If the UE is registered to the same PLMN through 3GPP access and non-3GPP access and the UE receives timer T3346 from AMF, timer T3346 may be applied to both 3GPP access and non-3GPP access.

If the UE receives a paging message or NOTIFICATION message when timer T3346 is running and the UE is registered to the same PLMN through 3GPP access and non-3GPP access, the UE stops timer T3346 for both accesses and receives the paging message or notification A response message can be sent to the message.

Timer T3346 is running when the UE enters the 5GMM-DEREGISTERED state, and if the UE remains on and the UE's USIM remains the same, timer T3346 may continue to run until it expires or is stopped.

If the UE enters a new PLMN while timer T3346 is running and the new PLMN is not the same as the PLMN from which the UE started timer T3346, the UE may stop timer T3346 when starting the 5GMM procedure in the new PLMN.

If timer T3346 is running after the registration area is changed and the 5GS update status is 5U1 UPDATED, the UE may set the 5GS update status to 5U2 NOT UPDATED and enter the 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE state.

If timer T3346 is running or disabled, the UE is a UE configured for high priority access in the selected PLMN, or the UE needs to initiate signaling for emergency services or emergency service fallback, the UE may initiate the 5GMM procedure.

B-1. Processing of DNN-based congestion control

AMF can detect and start performing DNN-based congestion control when one or more DNN congestion criteria are met. If the UE does not provide a DNN for the non-emergency PDU session, the AMF may use the selected DNN or the DNN associated with the PDU session corresponding to the 5GSM procedure.

B-2. Processing of S-NSSAI based congestion control

AMF can detect and start performing S-NSSAI-based congestion control when one or more S-NSSAI congestion criteria are met. If the UE does not provide a DNN for the non-emergency PDU session, the AMF may use the selected DNN or the DNN associated with the PDU session corresponding to the 5GSM procedure. If the UE does not provide an S-NSSAI for a non-emergency PDU session, AMF may use the selected S-NSSAI or S-NSSAI associated with the PDU session corresponding to the 5GSM procedure.

B-3. Processing of DNN-based congestion control

The network can detect and begin performing DNN-based congestion control when one or more DNN congestion criteria are met. If the UE does not provide a DNN for non-emergency PDU sessions, the network may use the selected DNN.

The 5GS session management timer T3396 for DNN-based congestion control in the UE can be started and stopped on a DNN basis, except for LADN DNN in the case of PLMN. In the case of LADN DNN, 5GS session management timer T3396 for DNN-based congestion control can be applied to registered PLMN and corresponding PLMN.

The DNN associated with T3396 may be the DNN provided by the UE during PDU session setup. If the DNN is not provided within the PDU SESSION ESTABLISHMENT REQUEST transmitted by the UE, T3396 may not be associated with the DNN. For this purpose, the UE must store the DNN provided to the network during PDU session setup. Timer T3396 associated with DNN may not start due to 5GSM procedures related to emergency PDU sessions. If timer T3396 associated with the DNN is running, this may not affect the UE's ability to request an emergency PDU session.

If T3396 is running or disabled, the UE cannot start:

a) PDU session setup procedure

b) PDU session modification procedure; or

c) NAS transmission procedure for transmitting CIoT user data;

B-4. Processing of S-NSSAI based congestion control

The network may detect and begin performing S-NSSAI-based congestion control when one or more S-NSSAI congestion criteria are met. If the UE does not provide a DNN for non-emergency PDU sessions, the network may use the selected DNN. If the UE does not provide S-NSSAI for non-emergency PDU sessions, the network may use the selected S-NSSAI.

For PLMN, the 5GS session management timer T3584 for S-NSSAI-based congestion control in the UE can be started and stopped on an S-NSSAI, DNN, and PLMN basis. If the 5GSM Congestion Retry Indicator IE with the ABO bit set to "Backoff timer applies to all PLMNs" is included in a 5GSM message with 5GSM cause value #67 "Insufficient resources for specific slices and DNNs", the UE shall not retry all PLMNs. Timer T3584 can be applied for . Otherwise, the UE may apply timer T3584 for the registered PLMN. If timer T3584 applies to all PLMNs, timer T3584 may be started when the UE is registered with the VPLMN and S-NSSAI is provided by the UE during PDU session setup. At this time, timer T3584 may be related to a combination of [mapped S-NSSAI, DNN] PDU sessions.

For PLMN, the 5GS session management timer T3585 for S-NSSAI-based congestion control in the UE can be started and stopped on an S-NSSAI and PLMN basis. If the 5GSM Congestion Retry Indicator IE with the ABO bit set to "Backoff timer applies to all PLMNs" is included in a 5GSM message with 5GSM cause value #69 "Insufficient resources for specific slice", the UE shall not apply to all PLMNs. The T3585 timer can be applied. Otherwise, the UE may apply timer T3585 for the registered PLMN. If timer T3585 applies to all PLMNs, timer T3585 may be started when the UE is registered with the VPLMN and S-NSSAI is provided by the UE during PDU session setup. Timer T3585 may be associated with a mapped S-NSSAI. Additionally, if the 5GSM Congestion Retry Indicator IE with the CATBO bit set to "Backoff timer applies to current access type" is included in a 5GSM message with 5GSM cause value #69 "Insufficient resources for specific slice"; The UE may apply timer T3585 for the current connection type, otherwise the UE may apply timer T3585 for both 3GPP access types and non-3GPP access types.

If timer T3584 or timer T3585 was provided during the PDU session establishment procedure, the S-NSSAI associated with T3584 or T3585 may be an S-NSSAI that does not include the S-NSSAI provided by the UE during PDU session establishment.

If timer T3584 is provided during the PDU session modification or PDU session release procedure, the UE may operate as follows. The DNN associated with T3584 may be the DNN provided by the UE during PDU session setup. If S-NSSAI is not provided by the UE through the PDU SESSION ESTABLISHMENT REQUEST message, and only a DNN is provided, the T3584 may be associated with the DNN provided to the network during PDU session setup, and may not be associated with the S-NSSAI. . If a PDN connection is established when in S1 mode, the T3584 may not associate with S-NSSAI. If the DNN is not provided by the UE through the PDU SESSION ESTABLISHMENT REQUEST message but the S-NSSAI is provided, T3584 may be associated with the DNN of the PDU session, but may not be associated with the S-NSSAI. If DNN and S-NSSAI are not provided in the PDU SESSION ESTABLISHMENT REQUEST message sent by the UE, T3584 may not be associated with DNN and S-NSSAI. For this purpose, the UE may need to store the DNN and S-NSSAI provided to the network during PDU session setup. Timer T3584 related to DNN and S-NSSAI may not start due to 5GSM procedures related to emergency PDU sessions. If timer T3584, which is only related to S-NSSAI and not DNN, is running, this will not affect the ability of the UE to request an emergency PDU session.

If timer T3585 is provided during the PDU session modification or PDU session release procedure, the UE may operate as follows. If S-NSSAI is not provided in the PDU SESSION ESTABLISHMENT REQUEST message sent by the UE, T3585 may not be associated with S-NSSAI. If a PDN connection is established when in S1 mode, the T3585 may not be able to connect to the S-NSSAI.

If T3584 is running or disabled, the UE cannot start:

a) PDU session setup procedure

b) PDU session modification procedure; or

c) NAS transmission procedure for transmitting CIoT user data;

If timer T3584 is running or disabled for all PLMNs and is associated with an S-NSSAI other than the S-NSSAI,

a) UE registered in HPLMN may not be allowed to initiate:

a-1) PDU session setup procedure;

a-2) PDU session modification procedure; or

a-3) NAS transmission procedure for transmitting CIoT user data;

b) UEs registered in the VPLMN may not be allowed to initiate:

b-1) PDU session setup procedure;

b-2) PDU session modification procedure; or

b-3) NAS transmission procedure for transmitting CIoT user data;

If timer T3584 is running or disabled for all PLMNs and is associated with [no S-NSSAI, no DNN] or [no S-NSSAI, DNN] combination, the UE may not be permitted to initiate:

a) PDU session setup procedure

b) PDU session modification procedure; or

c) NAS transmission procedure for transmitting CIoT user data;

If timer T3585 is running or disabled for all PLMNs and is associated with an S-NSSAI other than the S-NSSAI,

a) UE registered in HPLMN may not be allowed to initiate:

a-1) PDU session setup procedure;

a-2) PDU session modification procedure; or

a-3) NAS transmission procedure for transmitting CIoT user data;

b) UEs registered in the VPLMN may not be allowed to initiate:

b-1) PDU session setup procedure;

b-2) PDU session modification procedure; or

b-3) NAS transmission procedure for transmitting CIoT user data;

If the timer T3585 is running or is deactivated for all the PLMNs and is associated with no S-NSSAI, then the UE is not allowed to initiate the:

a) PDU establishment session procedure;

b) PDU session modification procedure;

c) NAS transport procedure for sending CIoT user data;

If timer T3585 is running or disabled for all PLMNs and there is no S-NSSAI, the UE may not be able to start:

a) PDU session setup procedure

b) PDU session modification procedure;

c) NAS transmission procedure for transmitting CIoT user data;

<Time-Sensitive Networking (TSN)>

On the other hand, time-sensitive networking (TSN) will be explained.

Ultra-low latency (URLLC; Ultra Reliable Low Latency Communications) networking for the 4th Industrial Revolution and 5G mobile communications to exchange and process information by organically connecting people and objects, online and offline, in the hyper-connected intelligent information society of the future. The technology is emerging as an essential network infrastructure-based technology. Accordingly, 3GPP is actively accepting the challenging requirements of vertical industrial domains and is developing automation-centered Industrial Internet of Things (IIoT) that can maximize industrial productivity and profitability through changes in communication infrastructure. Research is ongoing. In particular, mission-oriented industries such as smart factories, smart grids, and intelligent transportation systems require ultra-reliable, low-latency communication performance at the level of wired infrastructure, and new technologies to support this are being reflected in standards.

IEEE TSN technology emerged to implement the Industrial Internet of Things (IIoT), which seeks to connect various facilities and systems in industrial sites through a network. IEEE TSN technology is considered to be a next-generation industrial network standard that can cover most network applications by extending standard Ethernet into one package technology that combines several existing IEEE standards. In 3GPP, 5G-TSN technology has been promoted in earnest to standardize to spread 5G technology in vertical areas since Rel-16. 5G-TSN technology is basically a technology for integrating IEEE TSN technology into the 5G system (5GS) and is a time-sensitive communications technology (TSC) that defines and supports various IIoT service requirements. )am. TSC basically goes through a time synchronization process between 5GS and TSN. Afterwards, TSC QoS Flow based on TSCAI (TSC Assistance Information) is supported.

Figure 9 is an example diagram showing a network architecture interworking with a TSN network.

Referring to FIG. 9, the 5G system can be interworked with an external network through a TSN bridge. The logical TSN bridge may include TSN Translator functionality to enable interoperability between the 5GS system and the TSN system for both the user plane and the control plane. The 5GS TSN conversion function may include a device-side TSN translator (DS-TT) and a network-side TSN translator (NW-TT). TSN AF is part of 5GC and can provide control plane translation functionality to integrate 5GS with TSN. 5G system characteristic procedures, wireless communication links, etc. in 5GC and RAN may not be visible to the TSN network. 5GS provides TSN input ports (ingress) and output (egress) ports through DS-TT and NW-TT.

DS-TT can support link layer connection discovery and reporting to enable discovery of Ethernet devices connected to DS-TT. NW-TT can also support link layer connection discovery and reporting to discover Ethernet devices connected to NW-TT. When DS-TT does not support link layer connection discovery and reporting, NW-TT can discover Ethernet devices connected to DS-TT by performing link layer connection discovery and reporting on behalf of DS-TT. there is.

Figure 10 is an example diagram showing an architecture supporting time-sensitive communication and time synchronization services.

Referring to FIG. 10, DS-TT, NW-TT, and TSCTSF (Time Sensitive Communication and Time Synchronization Function) are shown to support time synchronization services for Ethernet or IP type sessions. NEF provides 5GS capability information to support time synchronization services. The TSCTSF controls DS-TT and NW-TT.

UPF/NW-TT transmits (g)PTP messages.

When a UPF supports more than one NW-TT, there may be a one-to-one association between the NW-TT and the network instance, or a one-to-one association may exist between the NW-TT and the network instance with DNN/S-NSSAI in the UPF. When multiple network instances exist within a UPF, each network instance can be considered logically separate.

<Deterministic Networking (DetNet)

The deterministic networking (DetNet) technology in progress at the IETF DetNet WG is a technology (Layer 3 technology) that expands the scope of application of Ethernet TSN technology (Layer 2 technology) and integrates it with IP and MPLS-based networks. Ultimately, DetNet technology refers to a technology that supports the expansion of Ethernet TSN technology (Layer 2 technology) to IP technology (Layer 3 technology). In 3GPP, TSC framework extension technologies are being reflected in the standard to support IETF DetNet technology from Rel-18 to 5GS.

<Problems to be solved through disclosure of this specification>

Meanwhile, the explosive increase in user data usage may cause problems in mobile communication networks becoming congested.

In the current 3GPP 5GS (5G System), when network congestion occurs in the CN (Core Network), NAS-level congestion control can generally be performed. According to NAS level congestion control, the network rejects UE (i.e. terminal) requests to change session settings for data transmission or requests related to registration or registration updates, and sets the back-off timer to the UE (i.e. , terminal) together. A UE (i.e., terminal) that receives a back-off timer along with a rejection message from the network operates the back-off timer. The UE (i.e., terminal) cannot perform any signaling request until the back-off timer expires.

This mechanism is NAS level congestion control, and is basically divided into MM (Mobility Management) congestion control and SM (Session Management) congestion control.

In situations where NAS-level congestion control is being performed, the back-off timer of the UE (i.e., terminal) operates exceptionally in the case of a de-registration request procedure performed from the network or a response to a paging message. Even so, the UE (i.e., terminal) can transmit an MM or SM signaling request to the network. In addition, even if the back-off timer of the UE (i.e., terminal) is running, as an exception, if the UE (i.e., terminal) requests emergency service or is set to high priority access, The UE (i.e., terminal) may transmit an MM or SM signaling request to the network. At this time, MM signaling request refers to Registration Request message, Service Request message, Deregistration Request message, UL NAS Transport message, and NAS message, and SM signaling request refers to PDU session establishment request ( This refers to NAS messages such as a Session Establishment Request message, a PDU Session Modification Request message, and a PDU Session Release Request message.

Meanwhile, in the case of industrial traffic, QoS requirements for latency are very strict. In particular, in the case of specific industrial traffic (such as TSN traffic, TSC traffic, DetNet traffic, URLLC traffic, or IIoT traffic) that needs to transmit urgent or important/special information, it must be transmitted very quickly. do.

Industrial traffic that is different from the above general traffic refers to time-sensitive/deterministic or URLLC (Ultra-Reliable Low Latency Communication) or IIoT (Industrial IoT (Internet of Things)) or TSC (Time-sensitive) traffic. It may refer to traffic for sensitive communication or traffic of a related session.

Therefore, even in congestion situations, when transmitting urgent or important TSN (or DetNet, TSC, DetNet, URLLC, IIoT) information (important/special information), it must be transmitted immediately and quickly, and the current 3GPP standard does not require such control. There is no transmission method.

In conclusion, for signaling such urgent or important TSN (or DetNet, TSC, DetNet, URLLC, IIoT) information traffic, a control method is needed to enable the terminal to transmit to the network even in congestion situations.

<Disclosure of this specification>

Accordingly, the purpose of the disclosures of this specification is to present a method for solving the above-mentioned problems.

I. First disclosure of this specification

Figure 11 is an exemplary diagram showing one disclosure of the present specification.

Hereinafter, it will be described with reference to FIG. 11.

1) A UE (or terminal) that supports (capable of) TSN (or DetNet, TSC, URLLC, IIoT) transmits NAS MM (Mobility Management) or SM (Session Management) signaling to transmit industrial information/traffic. In this case, NAS MM signaling (e.g., registration request message, service request message, deregistration request message, UL NAS Transport message) message or NAS SM signaling (e.g., PDU session establishment request message, PDU session modification request message, PDU session release request) The message includes configuration information/indication (e.g., NAS configured for TSN (or DetNet, TSC, URLLC, IIoT)) indicating TSN (or DetNet, TSC, URLLC, IIoT) and transmits it to the network.

Industrial traffic that is different from the above general traffic refers to time-sensitive/deterministic or URLLC (Ultra-Reliable Low Latency Communication) or IIoT (Industrial IoT (Internet of Things)) or TSC (Time-sensitive) traffic. It may refer to traffic for sensitive communication or traffic of a related session.

Meanwhile, based on the information/indication, the network (e.g., SMF or AMF) distinguishes whether the corresponding MM signaling or SM signaling is for TSN (or DetNet, TSC, URLLC, IIoT) traffic, and related QoS and You can proceed with the session setup procedure.

2) However, when congestion occurs in the network, the network (eg, AMF or SMF) rejects the NAS MM signaling or SM signaling request from the UE (or terminal) and transmits a rejection message.

In the case of MM signaling, the rejection message may be a registration request rejection message (or registration rejection message), a service request rejection message (or service rejection message), or a deregistration request rejection message (or a deregistration rejection message).

In the case of the SM signaling, the rejection message may include a PDU session establishment request rejection message (or PDU session establishment rejection message), a PDU session modification request rejection message (or PDU session modification rejection message), and a PDU session release request rejection message (or PDU session modification request rejection message). It may be a release rejection message).

The rejection message may include a rejection reason value and a back-off timer. Specifically, in the case of MM signaling, the rejection message includes a rejection cause value (e.g. #xy: congestion for TSN (or DetNet, TSC, URLLC, IIoT)) for the MM signaling request, and the MM back- It may include an off timer (eg T_abcd). In the case of SM signaling, the rejection message includes a rejection reason for SM signaling (e.g., #wz: insufficient resources for TSN (or DetNet, TSC, URLLC, IIoT)) and an SM back-off timer (e.g., T_efgh). It can be included.

At this time, the first value (eg, #22: congestion) among the rejection reason values for the existing MM signaling request may be reused as the rejection reason value. In addition, the rejection reason value is the first value (e.g., #26: insufficient resources), the second value (#67: insufficient resources for specific slice and DNN), and the third value (e.g., #26: insufficient resources) among the rejection reason values for the existing SM signaling request ( For example, one of #69: insufficient resources for specific slice) can be reused. Additionally, the MM back-off timer may be the first timer (eg, T3346) among existing timers. In addition, among existing timers, the SM back-off timer includes a first timer (e.g., T3396 for specific DNN and PLMN), a second timer (e.g., T3584 for specific DNN and S-NSSAI), and a third timer (e.g., T3585 for specific S-NSSAI and PLMN) can be reused.

3) The UE (or terminal) that receives the rejection message from the network stops the MM signaling request or SM signaling request procedure and operates the provided back-off timer.

Thereafter, until the back-off timer for MM signaling expires, the UE does not transmit any MM signaling request to the network.

Alternatively, the UE does not transmit any SM signaling request to the network until the back-off timer for SM signaling expires.

4) However, if urgent or important data occurs in the TSN (or DetNet, TSC, URLLC, IIoT)-related application layer of the UE (or terminal), the application layer of the UE (or terminal) notifies the NAS layer. .

5) Then, the NAS layer of the UE (or terminal) can selectively stop or ignore the running timer.

6) And the NAS layer of the UE (or terminal) may transmit an SM signaling request or an MM signaling request to the network. The SM signaling request may be, for example, a PDU session establishment request message, a PDU session modification request message, or a PDU session release request message. The MM signaling request may be a registration request message, service request message, deregistration request message, or UL NAS Transport message.

Meanwhile, in step 5, if the NAS layer does not stop the running timer, in order to transmit urgent or important data, the running timer can be ignored and an SM signaling request or MM signaling request can be transmitted to the network. there is.

The SM signaling request or MM signaling request may include indication/information indicating override or exception of congestion control (eg, overriding indication/information).

When the network receives an SM signaling request message including the indication/information from a UE (or a terminal) while controlling a congestion situation, the network does not reject it, but sends an acceptance message to accept it, so that the UE (or the terminal) terminal) to transmit emergency or important data.

Process 6 is explained in more detail as follows.

If the NAS layer of the UE (or terminal) is in the 5GMM IDLE state, it must be switched to the 5GMM Connected state for data transmission. To do this, a Service Request message must be transmitted to the network.

Accordingly, the NAS layer of the UE (or terminal) ignores the MM back-off timer (e.g., T3346) even if it is operating without stopping in step 5 and transmits a service request message to the network. At this time, the service request message may include indication/information (eg, overriding indication/information) indicating ignoring or exception to congestion control. Then, the network accepts the service request message rather than rejecting it.

When the NAS layer of the UE (or terminal) receives an acceptance message for the service request message, it switches to the 5GMM Connected state, and then sends an SM signaling request (e.g., PDU session establishment request message, PDU session modification request message, PDU session A release request message) is sent to the network. Upon receiving the acceptance message for the SM signaling request, the UE (or terminal) can transmit emergency or important data.

To explain once again, in order to transmit emergency or important data, the NAS layer of the UE (or terminal) sends SM signaling (e.g., PDU session establishment request message, PDU session modification request message, or PDU session release request message) to the network. Prior to transmission, MM signaling (e.g., registration request message, service request message, deregistration request message, or UL NAS Transport message) may need to be transmitted first. At this time, even if the MM back-off timer (e.g., T3346) is running, it is ignored, and the NAS layer of the UE (or terminal) sends an indication/information (e.g., overriding indication) indicating override or exception of congestion control in the MM signaling. /information) can be included and transmitted. Thereafter, upon receiving an acceptance message for MM signaling from the network, the NAS layer of the UE (or terminal) sends SM signaling (e.g., a PDU session establishment request message, a PDU session modification request message, or a PDU session release request message). ) can be transmitted over the network. However, even at this time, if the SM back-off timer is running, the NAS layer of the UE (or terminal) ignores the SM back-off timer, and provides indication/information indicating disregard or exception of congestion control in SM signaling. (e.g., overriding indication/information) is included and transmitted.

Even while controlling a congestion situation, the network receives MM signaling and SM signaling including indications/information (e.g., overriding indication/information) indicating ignoring or exception to the congestion control from the UE (or terminal). , Accept rather than reject.

However, if the indication/information indicating override or exception to the congestion control (e.g., overriding indication/information) is not included, the network recognizes that NAS signaling is not for transmitting emergency or important data and rejects it. I do it.

In the foregoing description, regardless of performing Process 1 or Process 3, other processes may be performed. That is, configuration information/indication (e.g., NAS configured for TSN (or DetNet, TSC, URLLC, or DetNet, TSC, URLLC, Even if IIoT)) is not included, other processes can be performed without problems. Additionally, even if the timer is not stopped in step 5, the timer may be ignored in step 6 and MM signaling or SM signaling may be transmitted.

II. Second disclosure of this specification

The contents of the above-described first disclosure may be operated in connection with access control of the RRC layer of the UE (or terminal).

The UE (or terminal) performs the operation according to the first disclosure described above in order to transmit emergency or important data. At this time, the NAS layer of the UE (or terminal) provides the RRC layer with configuration information/indication indicating TSN (or DetNet, TSC, URLLC, IIoT) and/or indication/information indicating ignoring or exception of congestion control (e.g., overriding indication/information) can be transmitted.

Then, the RRC layer can skip checking by access control (i.e. integrated access control) due to configuration information/indication indicating the TSN (or DetNet, TSC, URLLC, IIoT). To this end, the NAS layer of the UE (or terminal) may provide the RRC layer, including indication/information indicating skipping of access control (e.g., Access Control skip indication/information or UAC skip indication/information). In this case, the RRC layer delivers the RRC message including the NAS message by not performing a check for access control based on the indication/information.

III. Brief Summary of Disclosures Herein

One disclosure of this specification provides a method of operating in a terminal. The method includes driving a Mobility Management (MM) back-off timer or a Session Management (SM) back-off timer; When industrial traffic transmission is required, the method may include stopping or ignoring the MM back-off timer or the SM timer and transmitting SM signaling or MM signaling. The SM signaling or MM signaling may include information indicating override or exception of congestion control.

The industrial traffic may be: traffic for Time Sensitive Network (TSN), Time-Sensitive Communication (TSC), Deterministic Networking (DetNet), Ultra Reliable and Low Latency Communications (URLLC), or Industrial Internet of Things (IIoT). .

The industrial traffic may be urgent or important industrial traffic.

The SM signaling is: PDU (Protocol Data Unit) Session Establishment Request message, PDU Session Modification Request message, PDU Session Release Request message, or NAS (Non-Access Stratum) ) may contain at least one of the following messages.

The MM signaling may include at least one of: a Registration Request message, a Service Request message, a Deregistration Request message, or a UL (uplink) NAS (Non-Access Stratum) Transport message. You can.

The method may further include receiving a NAS reject message including a value for the MM back-off timer or a value for the SM back-off timer.

The NAS rejection message may include at least one of: a PDU session establishment rejection message, a PDU session modification rejection message, or a PDU session release rejection message.

The NAS rejection message may include at least one of: a registration rejection message, a service rejection message, or a deregistration rejection message.

The terminal may include an application layer, a Non-Access Stratum (NAS) layer, and a Radio Resource Control (RRC) layer.

In order to transmit the SM signaling or MM signaling, the NAS layer may transmit information indicating the industrial traffic or information indicating ignoring or exception of the congestion control to the RRC layer. Then, the RRC layer can skip the check for access control and transmit an RRC message to the base station based on information indicating the industrial traffic or information indicating ignoring or exception to the congestion control.

One disclosure of this specification provides a chipset mounted on a terminal. The chipset includes at least one processor; and may include at least one memory that stores instructions and is operably electrically connectable to the at least one processor. Based on the instruction being executed by the at least one processor, the operations performed include: driving a Mobility Management (MM) back-off timer or a Session Management (SM) back-off timer; When industrial traffic transmission is required, the method may include stopping or ignoring the MM back-off timer or the SM timer and transmitting SM signaling or MM signaling. The SM signaling or MM signaling may include information indicating override or exception of congestion control.

One disclosure of this specification provides a device for a terminal. The device includes a transmitter and receiver; at least one processor; and may include at least one memory that stores instructions and is operably electrically connectable to the at least one processor. Based on the instruction being executed by the at least one processor, the operations performed include: driving a Mobility Management (MM) back-off timer or a Session Management (SM) back-off timer; When industrial traffic transmission is required, the method may include stopping or ignoring the MM back-off timer or the SM timer and transmitting SM signaling or MM signaling. The SM signaling or MM signaling may include information indicating override or exception of congestion control.

Hereinafter, a device to which the above disclosure of the present specification can be applied will be described.

Figure 12 shows a block diagram of a processor on which the disclosure of the present specification is implemented.

As can be seen with reference to FIG. 12, the processor 1020 on which the disclosure of the present disclosure is implemented includes a plurality of circuitry to implement the proposed functions, procedures and/or methods described herein. can do. For example, the processor 1020 may include a first circuit 1020-1, a second circuit 1020-2, and a third circuit 1020-3. Additionally, although not shown, the processor 1020 may include more circuits. Each circuit may include a plurality of transistors.

The processor 1020 may be called an application-specific integrated circuit (ASIC) or an application processor (AP), and includes at least one of a digital signal processor (DSP), a central processing unit (CPU), and a graphics processing unit (GPU). can do.

The processor may be installed in the UE.

13 shows a wireless communication system according to one embodiment.

Referring to FIG. 13, a wireless communication system may include a first device 100a and a second device 100b.

The first device 100a may be the UE described in the disclosure of this specification. Alternatively, the first device 100a may be a base station, a network node, a transmitting UE, a receiving UE, a wireless device, a wireless communication device, a vehicle, a vehicle equipped with an autonomous driving function, a connected car, or a drone (Unmanned Aerial Vehicle). , UAV), AI (Artificial Intelligence) module, robot, AR (Augmented Reality) device, VR (Virtual Reality) device, MR (Mixed Reality) device, hologram device, public safety device, MTC device, IoT device, medical device, It may be a fintech device (or financial device), security device, climate/environment device, device related to 5G service, or other device related to the 4th Industrial Revolution field.

The second device 100b may be a network node (eg, AMF or MME) described in the disclosure of this specification. Alternatively, the second device 100b may be a base station, a network node, a transmitting UE, a receiving UE, a wireless device, a wireless communication device, a vehicle, a vehicle equipped with an autonomous driving function, a connected car, or a drone (Unmanned Aerial). Vehicle, UAV), AI (Artificial Intelligence) module, robot, AR (Augmented Reality) device, VR (Virtual Reality) device, MR (Mixed Reality) device, hologram device, public safety device, MTC device, IoT device, medical device , may be fintech devices (or financial devices), security devices, climate/environment devices, devices related to 5G services, or other devices related to the 4th Industrial Revolution field.

For example, the UE 100 may be a mobile phone, smart phone, laptop computer, digital broadcasting UE device, personal digital assistants (PDA), portable multimedia player (PMP), navigation, or slate PC. PC), tablet PC, ultrabook, wearable device (e.g., watch-type UE device (smartwatch), glass-type UE device (smart glass), HMD (head mounted display)) It may include etc. For example, an HMD may be a display device worn on the head. For example, HMD can be used to implement VR, AR or MR.

For example, a drone may be an aircraft that flies by radio control signals without a person on board. For example, a VR device may include a device that implements objects or backgrounds of a virtual world. For example, an AR device may include a device that connects an object or background in a virtual world to an object or background in the real world. For example, an MR device may include a device that fuses objects or backgrounds in the virtual world with objects or backgrounds in the real world. For example, a holographic device may include a device that records and reproduces three-dimensional information to create a 360-degree stereoscopic image by utilizing the light interference phenomenon that occurs when two laser lights meet, called holography. For example, a public safety device may include a video relay device or a video device that can be worn on the user's body. For example, MTC devices and IoT devices may be devices that do not require direct human intervention or manipulation. For example, MTC devices and IoT devices may include smart meters, bending machines, thermometers, smart light bulbs, door locks, or various sensors. For example, a medical device may be a device used for the purpose of diagnosing, treating, mitigating, treating, or preventing disease. For example, a medical device may be a device used for the purpose of diagnosing, treating, alleviating, or correcting an injury or disorder. For example, a medical device may be a device used for the purpose of examining, replacing, or modifying structure or function. For example, a medical device may be a device used for the purpose of controlling pregnancy. For example, medical devices may include medical devices, surgical devices, (in vitro) diagnostic devices, hearing aids, or surgical devices. For example, a security device may be a device installed to prevent risks that may occur and maintain safety. For example, a security device may be a camera, CCTV, recorder, or black box. For example, a fintech device may be a device that can provide financial services such as mobile payments. For example, a fintech device may include a payment device or a Point of Sales (POS). For example, a climate/environment device may include a device that monitors or predicts climate/environment.

The first device 100a may include at least one processor such as the processor 1020a, at least one memory such as the memory 1010a, and at least one transceiver such as the transceiver 1031a. The processor 1020a may perform the functions, procedures, and/or methods described above. The processor 1020a may perform one or more protocols. For example, the processor 1020a may perform one or more layers of a wireless interface protocol. The memory 1010a is connected to the processor 1020a and can store various types of information and/or commands. The transceiver 1031a is connected to the processor 1020a and can be controlled to transmit and receive wireless signals.

The second device 100b may include at least one processor such as the processor 1020b, at least one memory device such as the memory 1010b, and at least one transceiver such as the transceiver 1031b. The processor 1020b may perform the functions, procedures, and/or methods described above. The processor 1020b may implement one or more protocols. For example, the processor 1020b may implement one or more layers of a wireless interface protocol. The memory 1010b is connected to the processor 1020b and can store various types of information and/or commands. The transceiver 1031b is connected to the processor 1020b and can be controlled to transmit and receive wireless signals.

The memory 1010a and/or the memory 1010b may be respectively connected inside or outside the processor 1020a and/or the processor 1020b, and may be connected to other processors through various technologies such as wired or wireless connection. It may also be connected to .

The first device 100a and/or the second device 100b may have one or more antennas. For example, antenna 1036a and/or antenna 1036b may be configured to transmit and receive wireless signals.

Figure 14 illustrates a block diagram of a network node according to one embodiment.

In particular, FIG. 14 is a diagram illustrating in detail a case where the base station is divided into a central unit (CU) and a distributed unit (DU).

Referring to FIG. 14, base stations W20 and W30 may be connected to the core network W10, and base station W30 may be connected to a neighboring base station W20. For example, the interface between the base stations (W20, W30) and the core network (W10) may be referred to as NG, and the interface between the base station (W30) and the neighboring base station (W20) may be referred to as Xn.

The base station (W30) can be divided into CU (W32) and DU (W34, W36). That is, the base station W30 can be operated hierarchically separated. The CU (W32) may be connected to one or more DUs (W34, W36). For example, the interface between the CU (W32) and the DUs (W34, W36) may be referred to as F1. The CU (W32) can perform the functions of the upper layers of the base station, and the DUs (W34, W36) can perform the functions of the lower layers of the base station. For example, the CU (W32) is a logical node that hosts the radio resource control (RRC), service data adaptation protocol (SDAP), and packet data convergence protocol (PDCP) layers of a base station (e.g., gNB). may be, and the DUs (W34, W36) may be logical nodes that host the radio link control (RLC), media access control (MAC), and physical (PHY) layers of the base station. Alternatively, the CU (W32) may be a logical node hosting the RRC and PDCP layers of a base station (eg, en-gNB).

The operation of DUs (W34, W36) may be partially controlled by CU (W32). One DU (W34, W36) can support one or more cells. One cell can be supported by only one DU (W34, W36). One DU (W34, W36) can be connected to one CU (W32), and by appropriate implementation, one DU (W34, W36) can be connected to multiple CUs.

Figure 15 is a block diagram showing the configuration of the UE 100 according to an embodiment.

In particular, the UE 100 shown in FIG. 15 is a diagram illustrating the first device of FIG. 14 in more detail.

The UE 100 includes a memory 1010, a processor 1020, a transceiver 1031, a power management module 1091, a battery 1092, a display 1041, an input unit 1053, a speaker 1042, and a microphone ( 1052), a subscriber identification module (SIM) card, and one or more antennas.

Processor 1020 may be configured to implement the suggested functions, procedures and/or methods described herein. Layers of the air interface protocol may be implemented in processor 1020. Processor 1020 may include an application-specific integrated circuit (ASIC), other chipset, logic circuitry, and/or data processing devices. The processor 1020 may be an application processor (AP). The processor 1020 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). Examples of processors 1020 include SNAPDRAGONTM series processors manufactured by Qualcomm®, EXYNOSTM series processors manufactured by Samsung®, A series processors manufactured by Apple®, HELIOTM series processors manufactured by MediaTek®, INTEL® It may be an ATOMTM series processor manufactured by or a corresponding next-generation processor.

The power management module 1091 manages power for the processor 1020 and/or the transceiver 1031. Battery 1092 supplies power to power management module 1091. The display 1041 outputs the results processed by the processor 1020. Input unit 1053 receives input to be used by processor 1020. The input unit 1053 may be displayed on the display 1041. A SIM card is an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and its associated keys, which are used to identify and authenticate subscribers in mobile phone devices such as mobile phones and computers. You can also store contact information on many SIM cards.

The memory 1010 is operably coupled to the processor 1020 and stores various information for operating the processor 610. Memory 1010 may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and/or other storage devices. When an embodiment is implemented as software, the techniques described herein may be implemented as modules (eg, procedures, functions, etc.) that perform the functions described herein. Modules may be stored in memory 1010 and executed by processor 1020. The memory 1010 may be implemented inside the processor 1020. Alternatively, the memory 1010 may be implemented external to the processor 1020 and may be communicatively connected to the processor 1020 through various means known in the art.

The transceiver 1031 is operably coupled to the processor 1020 and transmits and/or receives wireless signals. The transceiver unit 1031 includes a transmitter and a receiver. The transceiver 1031 may include a baseband circuit for processing radio frequency signals. The transceiver controls one or more antennas to transmit and/or receive wireless signals. The processor 1020 transmits command information to the transceiver 1031 to initiate communication, for example, to transmit a wireless signal constituting voice communication data. The antenna functions to transmit and receive wireless signals. When receiving a wireless signal, the transceiver 1031 may transfer the signal and convert the signal to baseband for processing by the processor 1020. The processed signal may be converted into audible or readable information output through the speaker 1042.

The speaker 1042 outputs sound-related results processed by the processor 1020. Microphone 1052 receives sound-related input to be used by processor 1020.

The user inputs command information such as a phone number, for example, by pressing (or touching) a button on the input unit 1053 or by voice activation using the microphone 1052. The processor 1020 receives this command information and processes it to perform appropriate functions, such as calling a phone number. Operational data can be extracted from the SIM card or memory 1010. Additionally, the processor 1020 may display command information or driving information on the display 1041 for the user's recognition and convenience.

FIG. 16 is a block diagram showing in detail the transceiver unit of the first device shown in FIG. 13 or the transceiver unit of the device shown in FIG. 15.

Referring to FIG. 16, the transceiver 1031 includes a transmitter 1031-1 and a receiver 1031-2. The transmitter (1031-1) includes a Discrete Fourier Transform (DFT) unit (1031-11), a subcarrier mapper (1031-12), an IFFT unit (1031-13), a CP insertion unit (1031-14), and a wireless transmitter (1031). -15). The transmitter 1031-1 may further include a modulator. In addition, it may further include, for example, a scramble unit (not shown), a modulation mapper (not shown), a layer mapper (not shown), and a layer permutator (not shown), This may be placed prior to the DFT unit 1031-11. That is, in order to prevent an increase in the peak-to-average power ratio (PAPR), the transmitter 1031-1 first passes information through the DFT 1031-11 before mapping the signal to the subcarrier. The signal spread (or precoded in the same sense) by the DFT unit 1031-11 is subcarrier mapped through the subcarrier mapper 1031-12, and then again in the IFFT (Inverse Fast Fourier Transform) unit 1031-12. 13) to create a signal on the time axis.

The DFT unit 1031-11 performs DFT on the input symbols and outputs complex-valued symbols. For example, when Ntx symbols are input (where Ntx is a natural number), the DFT size is Ntx. The DFT unit 1031-11 may be called a transform precoder. The subcarrier mapper 1031-12 maps the complex symbols to each subcarrier in the frequency domain. The complex symbols may be mapped to resource elements corresponding to resource blocks allocated for data transmission. The subcarrier mapper 1031-12 may be called a resource element mapper. The IFFT unit 1031-13 performs IFFT on the input symbols and outputs a baseband signal for data that is a time domain signal. The CP insertion unit 1031-14 copies a part of the latter part of the basic band signal for data and inserts it into the front part of the basic band signal for data. Through CP insertion, ISI (Inter-Symbol Interference) and ICI (Inter-Carrier Interference) are prevented, and orthogonality can be maintained even in multi-path channels.

On the other hand, the receiver 1031-2 includes a wireless reception unit 1031-21, a CP removal unit 1031-22, an FFT unit 1031-23, and an equalization unit 1031-24. The wireless receiving unit 1031-21, CP removing unit 1031-22, and FFT unit 1031-23 of the receiver 1031-2 are the wireless transmitting unit 1031-15 in the transmitting end 1031-1, It performs the reverse function of the CP insertion unit (1031-14) and the IFF unit (1031-13). The receiver 1031-2 may further include a demodulator.

<Scenarios to which the disclosure of this specification can be applied>

Although not limited thereto, the various descriptions, functions, procedures, suggestions, methods, and/or operational flowcharts of the disclosure disclosed herein may be applied to various fields requiring wireless communication/connection (e.g., 5G) between devices. It can be applied.

Hereinafter, a more detailed example will be provided with reference to the drawings. In the following drawings/descriptions, identical reference numerals may illustrate identical or corresponding hardware blocks, software blocks, or functional blocks, unless otherwise noted.

17 illustrates a communication system 1 to which the disclosure of this specification applies.

Referring to FIG. 17, the communication system 1 to which the disclosure of this specification applies includes a wireless device, a base station, and a network. Here, a wireless device refers to a device that performs communication using wireless access technology (e.g., 5G NR (New RAT), LTE (Long Term Evolution)) and may be referred to as a communication/wireless/5G device. Although not limited thereto, wireless devices include robots (100a), vehicles (100b-1, 100b-2), XR (eXtended Reality) devices (100c), hand-held devices (100d), and home appliances (100e). ), IoT (Internet of Thing) device (100f), and AI device/server (400). For example, vehicles may include vehicles equipped with wireless communication functions, autonomous vehicles, vehicles capable of inter-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (eg, a drone). XR devices include AR (Augmented Reality)/VR (Virtual Reality)/MR (Mixed Reality) devices, HMD (Head-Mounted Device), HUD (Head-Up Display) installed in vehicles, televisions, smartphones, It can be implemented in the form of computers, wearable devices, home appliances, digital signage, vehicles, robots, etc. Portable devices may include smartphones, smart pads, wearable devices (e.g., smartwatches, smart glasses), and computers (e.g., laptops, etc.). Home appliances may include TVs, refrigerators, washing machines, etc. IoT devices may include sensors, smart meters, etc. For example, a base station and network may also be implemented as wireless devices, and a specific wireless device 200a may operate as a base station/network node for other wireless devices.

Wireless devices 100a to 100f may be connected to the network 300 through the base station 200. AI (Artificial Intelligence) technology may be applied to wireless devices (100a to 100f), and the wireless devices (100a to 100f) may be connected to the AI server 400 through the network 300. The network 300 may be configured using a 3G network, 4G (eg, LTE) network, or 5G (eg, NR) network. Wireless devices 100a to 100f may communicate with each other through the base station 200/network 300, but may also communicate directly (e.g. sidelink communication) without going through the base station/network. For example, vehicles 100b-1 and 100b-2 may communicate directly (e.g. V2V (Vehicle to Vehicle)/V2X (Vehicle to everything) communication). Additionally, an IoT device (eg, sensor) may communicate directly with another IoT device (eg, sensor) or another wireless device (100a to 100f).

Wireless communication/connection (150a, 150b, 150c) may be established between the wireless devices (100a to 100f)/base station (200) and the base station (200)/base station (200). Here, wireless communication/connection includes various wireless connections such as uplink/downlink communication (150a), sidelink communication (150b) (or D2D communication), and inter-base station communication (150c) (e.g. relay, IAB (Integrated Access Backhaul)). This can be achieved through technology (e.g., 5G NR). Through wireless communication/connection (150a, 150b, 150c), a wireless device and a base station/wireless device, and a base station and a base station can transmit/receive wireless signals to each other. Example For example, wireless communication/connection 150a, 150b, 150c can transmit/receive signals through various physical channels.To this end, based on the various proposals of the disclosure herein, transmit/receive wireless signals At least some of various configuration information setting processes, various signal processing processes (e.g., channel encoding/decoding, modulation/demodulation, resource mapping/demapping, etc.), resource allocation processes, etc. may be performed.

In the above, preferred embodiments have been described by way of example, but the disclosure of the present specification is not limited to these specific embodiments, and may be modified, changed, or modified in various forms within the scope described in the spirit and claims of the present specification. It can be improved.

In the example system described above, the methods are described on the basis of a flow chart as a series of steps or blocks, but the order of steps described is not limited, and some steps may occur simultaneously or in a different order than other steps as described above. there is. Additionally, those skilled in the art will understand that the steps shown in the flowchart are not exclusive and that other steps may be included or one or more steps in the flowchart may be deleted without affecting the scope of rights.

The claims set forth herein may be combined in various ways. For example, the technical features of the method claims of this specification may be combined to implement a device, and the technical features of the device claims of this specification may be combined to implement a method. Additionally, the technical features of the method claims of this specification and the technical features of the device claims may be combined to implement a device, and the technical features of the method claims of this specification and technical features of the device claims may be combined to implement a method.

Claims (20)

As an operation method in the terminal,
driving a Mobility Management (MM) back-off timer or a Session Management (SM) back-off timer;
When industrial traffic transmission is necessary, stopping or ignoring the MM back-off timer or the SM timer and transmitting SM signaling or MM signaling,
The SM signaling or MM signaling includes information indicating override or exception of congestion control. The method of claim 1, wherein the industrial traffic is
A traffic-in method for Time Sensitive Network (TSN), Time-Sensitive Communication (TSC), Deterministic Networking (DetNet), Ultra Reliable and Low Latency Communications (URLLC), or Industrial Internet of Things (IIoT). The method of claim 1, wherein the industrial traffic is urgent or important industrial traffic. The method of claim 1, wherein the SM signaling:
At least one of a Protocol Data Unit (PDU) Session Establishment Request message, a PDU Session Modification Request message, a PDU Session Release Request message, or a Non-Access Stratum (NAS) message. Method, including. The method of claim 1, wherein the MM signaling:
A method including at least one of a Registration Request message, a Service Request message, a Deregistration Request message, or an uplink (UL) Non-Access Stratum (NAS) Transport message. The method of claim 1, further comprising receiving a NAS reject message including a value for the MM back-off timer or a value for the SM back-off timer. The method of claim 6, wherein the NAS rejection message:
A method including at least one of a PDU session establishment rejection message, a PDU session modification rejection message, and a PDU session release rejection message. The method of claim 6, wherein the NAS rejection message:
A method including at least one of a registration rejection message, a service rejection message, and a deregistration rejection message. The method of claim 1, wherein the terminal includes an application layer, a Non-Access Stratum (NAS) layer, and a Radio Resource Control (RRC) layer,
To transmit the SM signaling or MM signaling,
The NAS layer transmits information indicating the industrial traffic or information indicating override or exception of the congestion control to the RRC layer; and
The RRC layer skips the check for access control and transmits an RRC message to the base station based on information indicating the industrial traffic or information indicating ignoring or exception to the congestion control.
As a chipset mounted on a terminal,
at least one processor; and
At least one memory for storing instructions, operably electrically connectable with the at least one processor, and based on the instructions being executed by the at least one processor, perform The behavior is:
driving a Mobility Management (MM) back-off timer or a Session Management (SM) back-off timer;
When industrial traffic transmission is necessary, stopping or ignoring the MM back-off timer or the SM timer and transmitting SM signaling or MM signaling,
The SM signaling or MM signaling includes information indicating override or exception of congestion control. The method of claim 10, wherein the industrial traffic is
Traffic-in, chipsets for Time Sensitive Network (TSN), Time-Sensitive Communication (TSC), Deterministic Networking (DetNet), Ultra Reliable and Low Latency Communications (URLLC), or Industrial Internet of Things (IIoT). The chipset of claim 10, wherein the industrial traffic is urgent or important industrial traffic. The method of claim 10, wherein the SM signaling:
At least one of a Protocol Data Unit (PDU) Session Establishment Request message, a PDU Session Modification Request message, a PDU Session Release Request message, or a Non-Access Stratum (NAS) message. Including chipset. The method of claim 10, wherein the MM signaling:
A chipset including at least one of a Registration Request message, a Service Request message, a Deregistration Request message, or an uplink (UL) Non-Access Stratum (NAS) Transport message. 11. The method of claim 10, wherein the operations are:
The chipset further comprising receiving a NAS reject message including a value for the MM back-off timer or a value for the SM back-off timer. The method of claim 10, wherein the processor includes an application layer, a Non-Access Stratum (NAS) layer, and a Radio Resource Control (RRC) layer,
To transmit the SM signaling or MM signaling,
The NAS layer transmits information indicating the industrial traffic or information indicating override or exception of the congestion control to the RRC layer, and
The RRC layer skips the check for access control and transmits an RRC message to the base station based on information indicating the industrial traffic or information indicating ignoring or exception to the congestion control.
As a device for a terminal,
Transmitter and receiver;
at least one processor; and
At least one memory that stores instructions and is operably electrically connectable to the at least one processor,
Based on the instruction being executed by the at least one processor, the operations performed are:
driving a Mobility Management (MM) back-off timer or a Session Management (SM) back-off timer;
When industrial traffic transmission is necessary, stopping or ignoring the MM back-off timer or the SM timer and transmitting SM signaling or MM signaling,
The SM signaling or MM signaling includes information indicating override or exception of congestion control. The method of claim 17, wherein the industrial traffic is
Traffic-in, devices for Time Sensitive Network (TSN), Time-Sensitive Communication (TSC), Deterministic Networking (DetNet), Ultra Reliable and Low Latency Communications (URLLC), or Industrial Internet of Things (IIoT). The apparatus of claim 17, wherein the industrial traffic is urgent or important industrial traffic. The method of claim 17, wherein the processor includes an application layer, a Non-Access Stratum (NAS) layer, and a Radio Resource Control (RRC) layer,
To transmit the SM signaling or MM signaling,
The NAS layer transmits information indicating the industrial traffic or information indicating override or exception of the congestion control to the RRC layer, and
The RRC layer skips the check for access control and transmits an RRC message to the base station based on information indicating the industrial traffic or information indicating ignoring or exception to the congestion control.

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