KR102580332B1 - Method and Apparatus for Controlling Congestion in Communication Systems with Services - Google Patents

Abstract

Disclosed is a method and device for controlling network congestion for each service.
Embodiments of the present invention provide a method for protecting the network from congestion while improving the quality of service experienced by the user by considering the different characteristics of each function when congestion occurs in network functions within a slice in a network slicing-based mobile communication system. The main purpose is to provide and devices.

Description

Method and Apparatus for Controlling Congestion in Communication Systems with Services}

This embodiment relates to a method and apparatus for controlling network congestion in a mobile communication system where one physical network is divided into separate logical networks according to the type of user subscription service.

The content described in this section simply provides background information for this embodiment and does not constitute prior art.

Conventional mobile communication systems have been optimized for specific services rather than providing a variety of services. For example, conventionally, networks were structured in a structure optimized only for mobile phone terminals. However, in the next-generation mobile communication system, a network structure that can provide services not only to mobile phone terminals but also to various terminals with different properties is required.

For example, Enhanced Mobile Broadband (e.g. UHD, VR video, etc.), Massive Machine Type Communications (e.g. smart city, smart home, etc.), which are presented as representative use cases of next-generation mobile communication systems, and Ultra- Reliable and Low Latency Communications (e.g. self-driving cars, factory automation, etc.) have different service properties and network requirements in terms of mobility, billing, security, latency, and reliability.

Accordingly, network slicing is being discussed as a technology for configuring a network appropriately for each service type. Network slicing is a technology that logically separates one physical network according to service type and provides multiple dedicated networks specialized for each service. Here, each logically separated network is called a network slice.

In the next-generation mobile communication system that applies network slicing, various functions within the network can be virtualized and implemented in one device, so unlike cases where congestion occurs in a conventional single network, congestion may occur in each network function. You can. Accordingly, a congestion control method that takes into account the characteristics of each network function is needed in the next-generation mobile communication system.

Embodiments of the present invention provide a method for protecting the network from congestion while improving the quality of service experienced by the user by considering the different characteristics of each function when congestion occurs in network functions within a slice in a network slicing-based mobile communication system. The main purpose is to provide and devices.

The problems to be solved by the embodiments of the present invention are not limited to those mentioned above, and other problems to be solved that are not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below. .

According to an embodiment of the present invention, a method for a network device to control network congestion in a mobile communication system in which one physical network is divided according to service type and consists of a plurality of slices, which are logical networks, within the plurality of slices. Obtaining congestion information from mobility management nodes, selecting a specific slice according to a registration request message for a specific type of slice received from the terminal device, and determining the congestion status of the mobility management node within the selected specific slice based on the congestion information. Confirming, and performing a registration procedure with the selected specific slice depending on whether congestion occurs in the mobility management node within the selected specific slice, or transmitting a registration rejection message including a back off timer to the terminal device. Provides a network congestion control method including:

According to an embodiment of the present invention, in a method for a terminal device to control network congestion in a mobile communication system in which one physical network is divided according to service type and consists of a plurality of slices, which are logical networks, the slice type to be connected is selected. and transmitting a registration request message for a slice of the selected type to the network device, receiving a registration rejection message including a backoff timer due to congestion of the mobility management node in the slice of the selected type from the network device, and rejecting registration. Provides a network congestion control method that includes waiting without requesting registration until a backoff timer expires depending on the message, or transmitting a registration request message for a preset slice type to a network device.

According to an embodiment of the present invention, in a method for a network device to control network congestion in a mobile communication system in which one physical network is divided according to service type and consists of a plurality of slices, which are logical networks, one in each slice is provided. Obtaining congestion information from the above session management nodes, receiving a session establishment request message for a specific type of session within a specific type of slice from a terminal device, and managing a specific session within the specific type of slice in the session establishment request message. A step of selecting a node and checking the congestion status of the selected specific session management node based on congestion information. And network congestion, including performing a session establishment procedure with a specific session management node or transmitting a session rejection message including a back off timer to the terminal device depending on whether congestion occurs in the selected specific session management node. Provides a control method.

In a method for a terminal device to control network congestion in a mobile communication system in which a physical network is divided according to service type and consists of a plurality of slices, which are logical networks, session establishment for a specific type of session within a specific type of slice Transmitting a request message to a network device, receiving a session rejection message including a backoff timer from the network device due to congestion of a specific session management node in a specific type of slice selected according to the session establishment request message, and session rejection. Provides a network congestion control method that includes waiting without requesting registration with a specific type of slice until the backoff timer expires according to the message, or transmitting a registration request message for a preset slice type to a network device. .

According to an embodiment of the present invention, a method for a network device to control network congestion in a mobile communication system in which one physical network is divided according to service type and consists of a plurality of slices, which are logical networks, includes one or more slices within a specific slice. Obtaining congestion information from one or more user plane nodes linked to session management nodes, receiving a session establishment request message for a specific type of session within a specific type of slice from a terminal device, according to the session establishment request message. Checking the congestion status of one or more user plane nodes linked to a specific session management node based on congestion information, selecting a user plane node in which congestion does not occur, and transmitting information about the selected user plane node to the base station device. and transmitting information about the base station device to the selected user plane node to perform a session establishment procedure.

As described above, according to embodiments of the present invention, when congestion occurs in network functions within a slice in a network slicing-based mobile communication system, the user's perceived quality of service is improved by taking into account the different characteristics of each function, and the network It has the effect of protecting from congestion.

According to an embodiment of the present invention, there is an effect of increasing the efficiency of using overall network resources by controlling congestion according to the characteristics of the network function where congestion occurs in a mobile communication system to which network slicing is applied.

According to an embodiment of the present invention, it is possible to use the optimal network slice and QoS in consideration of the service usage status of the terminal device and the type of subscribed service in a network congestion situation.

1 is a schematic structural diagram of a network slicing-based mobile communication system related to an embodiment of the present invention.
Figure 2 is a flowchart showing a congestion control method of a network device and a terminal device when congestion occurs in a mobility management node within a network slice according to an embodiment of the present invention.
Figure 3 is a flowchart showing a congestion control method of a network device and a terminal device when congestion occurs in a session management node within a network slice according to an embodiment of the present invention.
Figure 4 is a flowchart showing a congestion control method of a network device and a terminal device when congestion occurs in a user plane node within a network slice according to an embodiment of the present invention.
Figure 5 is a flowchart showing a congestion control method of a network device and a terminal device when congestion occurs in a user plane node within a network slice according to another embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to the attached drawings. In explaining the present invention, '... Terms such as 'unit' and 'module' refer to a unit that processes at least one function or operation, and may be implemented as hardware, software, or a combination of hardware and software.

An embodiment of the present invention is a method of protecting the network from congestion while improving the quality of service experienced by the user by considering the different characteristics of each function when congestion occurs in network functions within a slice in a mobile communication system based on network slicing. and a device are proposed.

1 is a schematic structural diagram of a network slicing-based mobile communication system related to an embodiment of the present invention.

Referring to FIG. 1, the network slicing-based mobile communication system 100 includes a plurality of network slices 110, a terminal device (UE) 150, a Radio Access Network (RAN) 140, and a Public Data Network (PDN) 160. Includes. Although only one network slice is shown in FIG. 1 for convenience of explanation, the mobile communication system 100 includes a plurality of network slices specialized for each service type. A detailed description of the network slice (hereinafter referred to as ‘slice’) is as follows.

Each slice is an independent logical network dedicated to a specific service, and when the terminal device 150 connects to the network, an appropriate slice is selected from a plurality of slices according to the user's subscription information.

One slice structure is divided into a control plane (120) and a user plane (130), and the control plane (120) includes a mobility management node (MM: 122) and a session management node (SM: Session). Management, 124), etc. are included, and the user plane 130 may include a user plane node (UPGW: User Plane Gateway, 132).

The mobility management node 122, session management node 124, and user plane node 132 may be implemented in a form in which software for each network function is mounted on a single virtualized network device. In other words, it refers to a node that provides each function as a virtualized node rather than a physical node.

A network device according to an embodiment of the present invention may be implemented with a plurality of slices, and each slice may include a mobility management node 122, one or more session management nodes 124, and one or more user plane nodes 132. You can. Here, the network device may include one or more processors to perform each network function, and may include a transmission/reception module for communication with the terminal device and the base station device.

One or more session management nodes 124 may be linked to one mobility management node 122, and one or more user plane nodes 132 may be linked to each of one session management nodes 124. In other words, one slice is multi-layered (hierarchical) in which a plurality of session management nodes 124 are linked to one mobility management node 122, and a plurality of user plane nodes 132 are linked to one session management node 124. It can be composed of a structure. Here, the session management node 124 may be defined by traffic characteristics or service characteristics.

The mobility management node 122 performs the function of managing the overall status of the terminal device 150, such as authentication, connection management, and mobility management, and the session management node 124 performs session-based traffic transmission such as session management and QoS management. It performs a management function, and the user plane node 132 performs a function of transmitting user data packets from one node to another node.

In the network slicing-based mobile communication system 100, congestion may occur in network functions (i.e., MM, SM, UPGW, etc.) within each slice, which is a logical network. Since each network function is mounted within a single network device, physically limited resources such as computing, memory, and network are used. Accordingly, congestion occurs when the amount to be processed is greater than the resources allocated to each network function.

Here, the throughput of each function is the number of connected terminal devices in the case of the mobility management node 122, the number of sessions managed in the case of the session management node 124, and the number of sessions in the case of the user plane node 132. In addition, it can be expressed as the number of packets actually processed.

When congestion occurs in each function within a slice, if congestion control is not properly performed, the network may malfunction due to the congestion, and if congestion control is performed excessively, the quality of service experienced by the user may actually deteriorate. Therefore, a method is needed to control congestion so that the network operates appropriately while increasing the user-perceived service quality by considering the different characteristics of each function within the slice.

Hereinafter, with reference to FIGS. 2 to 5, a method for controlling congestion in each case when congestion occurs in each network function within a slice will be described in detail.

Figure 2 is a flowchart showing a congestion control method of a network device and a terminal device when congestion occurs in the mobility management node 122 within a network slice according to an embodiment of the present invention.

The network device (not shown) of this embodiment implements the functions of a slice selection node and mobility management nodes included in each slice (slice 1, slice 2, ..., slice n). However, the slice selection node may be implemented in a base station device (not shown). The slice selection node selects an appropriate slice according to subscriber information (subscription) of the terminal device 150 when the terminal device 150 connects to the network.

In the above-described network structure, the mobility management node 122 performs the function of processing the slice connection of the terminal device 150, and session establishment requests to all session management nodes 124 are transmitted and received only through the mobility management node 122. do. Since the mobility management node 122 performs the function of processing slice connections, additional connections to the slice should not be allowed when congestion occurs. In addition, it is necessary to control the terminal device 150 to stop and wait for a connection request until congestion in the mobility management node 122 is resolved, or to connect to another slice.

To this end, the network device according to an embodiment of the present invention obtains congestion information from mobility management nodes within a plurality of slices (S210). Figure 2 simply shows a case where only the mobility management node in slice 1 transmits congestion information, but the mobility management nodes in the remaining slices also transmit congestion information to the slice selection node.

The intra-slice mobility management node 122 may detect that congestion has occurred and transmit congestion information to the slice selection node. Here, the congestion information is information indicating a congestion state based on the maximum number of terminal devices that can connect to the mobility management node 122 and the number of terminal devices in a connected state, and may indicate at least one of the congestion level and whether congestion has occurred.

For example, the congestion level can be expressed as a ratio of the number of terminal devices currently connected to the maximum number of terminal devices that can be connected, and whether congestion occurs can be simply expressed as a bit indicating congestion/non-congestion.

When connecting to the network, the terminal device 150 selects a slice type to connect according to the service type (S212) and transmits a registration request message to the slice selection node (S214). The registration request message includes information about the selected slice type.

The slice selection node selects a specific slice of the requested type among a plurality of slices according to the registration request message received from the terminal device 150, and checks the congestion status of the mobility management node within the selected specific slice based on the congestion information ( S216). The example in FIG. 2 shows a case where the mobility management node of slice 1 is selected to check the congestion state.

In step S216, the slice selection node can check the congestion state by checking the bit indicating congestion or the congestion level included in the congestion information. For example, the bit indicating congestion can be defined as 1 for congestion and 0 for non-congestion. If the bit indicating congestion is 1, it can be determined that congestion has occurred in the mobility management node within the slice. there is. Of course, the opposite case is also possible. As another example, if the congestion level (i.e., a numerical value representing the degree of congestion) is greater than or equal to a preset threshold, it may be determined that congestion has occurred.

The slice selection node may perform a registration procedure with the specific selected slice or transmit a registration rejection message including a back off timer to the terminal device 150, depending on whether congestion occurs in the mobility management node determined in step S216. there is. If it is confirmed that congestion has occurred in the corresponding mobility management node, the slice selection node transmits a registration rejection message to reject the registration request of the terminal device 150 (S218). At this time, the registration rejection message may include a backoff timer and a reason indicating that the request was rejected due to congestion.

The time value of the backoff timer can be set by the slice selection node based on congestion information received from the mobility management node. For example, if it is confirmed that congestion has occurred based on congestion information, the backoff timer can be set to a predetermined time, or the backoff timer can be set variably according to the congestion level. The backoff timer may be set at the slice selection node as described above, but it is not necessarily limited to this, and the mobility management node may directly detect the congestion state and set the backoff timer according to the congestion level and transmit it along with the congestion information. .

When the terminal device 150 receives a registration rejection message from the slice selection node, the backoff timer included in the registration rejection message starts, and remains in the slice for a predetermined time until the backoff timer expires. Either wait without requesting registration, or select a slice type different from the slice for which registration was rejected (S220).

When selecting a slice type different from the slice for which registration has been rejected, the terminal device 150 has information for selecting a different slice. In this case, the other slice type selected by the terminal device 150 is a preset slice type, for example, is set as the default slice type or selects the next priority slice according to the priority list for the slice type. It can also be set to select. The default slice type may be a slice type to provide minimum essential services, such as emergency calls, for example.

The terminal device 150 transmits a registration request message for another selected slice type (i.e., a preset slice type) to the slice selection node (S222). The slice selection node selects a slice again according to the second registration request from the terminal device 150, checks the congestion status of the mobility management node within the slice (S224), and if it is not congested as a result of the check, the corresponding mobility management node (e.g. : A registration request message is delivered to the mobility management node within slice n (S226). Afterwards, the network device of this embodiment performs the remaining registration procedures with the terminal device (S228).

Figure 3 is a flowchart showing a congestion control method of a network device and a terminal device when congestion occurs in a session management node within a network slice according to an embodiment of the present invention. The network device (not shown) of this embodiment implements the functions of a plurality of intra-slice mobility management nodes and one or more session management nodes linked thereto. In Figure 3, for clarity of explanation, only the mobility management node within a specific slice among a plurality of slices is shown.

In the conventional mobile communication system, when the terminal device is registered (attached) to the network, a session (i.e., PDN connection) is unconditionally created and the service is provided. However, in the mobile communication system 100 according to the embodiment of the present invention, the session is unconditionally created. Rather than creating a session, you can provide a specific service by creating a session only when necessary.

The congestion control method according to an embodiment of the present invention is a method of distinguishing between services for which session establishment is mandatory and services for which it is optional, and controlling the session management node 124 where congestion occurs according to each service. can be changed.

For example, when a terminal device requests access to a specific slice for a service that requires session establishment, if congestion occurs in the session management node that manages the session, access to the slice is no longer meaningful, so other It is necessary to select a slice or wait until the congestion clears.

In the opposite case, there is a service that does not require session establishment during the process of the terminal device selecting a slice and performing the registration procedure (i.e., a service that only needs to create a session when data transmission and reception is necessary). In this case, even if congestion occurs at the session management node required during the process of accessing the slice, access to the slice is possible.

The terminal device 150 according to this embodiment may include information on whether registration with the session management node 124 is required when requesting a connection by selecting a slice. Here, information about whether registration with the session management node 124 is necessary may include information about whether session establishment (or allocation of a session management node) is necessary and information about which session management node to register with. .

Hereinafter, this embodiment will be described in detail with reference to FIG. 3.

The network device of this embodiment obtains congestion information from one or more session management nodes in each slice (S310). Session management nodes can detect that congestion has occurred and transmit congestion information to the mobility management node. Here, the congestion information is information indicating a congestion state based on the maximum number of sessions that the session management node can manage and the number of sessions being managed, and may indicate at least one of the congestion level and whether congestion has occurred.

For example, the congestion level can be expressed as a ratio of the number of sessions currently being managed to the maximum number of sessions that can be managed, and whether congestion occurs can be simply expressed as a bit indicating congestion/non-congestion.

When connecting to the network, the terminal device selects a slice type to connect according to the service type (S312) and transmits a session establishment request message for a specific type of session within the selected specific type of slice to the corresponding mobility management node (S314). . Here, the session establishment request message may be included in the registration request message for a specific type of slice and delivered to the mobility management node. Additionally, the session establishment request message may include a flag indicating whether session establishment is essential.

The mobility management node selects a specific session management node within a specific type of slice according to the session establishment request message received from the terminal device, and checks the congestion status of the selected specific session management node based on the congestion information (S316).

In step S316, the mobility management node can check the congestion status by checking the bit or congestion level indicating congestion included in the congestion information. For example, the bit indicating congestion can be defined as 1 for congestion and 0 for non-congestion. If the bit indicating congestion is 1, it can be determined that congestion has occurred in the session management node. Of course, the opposite case is also possible. As another example, if the congestion level (i.e., a numerical value representing the degree of congestion) is greater than or equal to a preset threshold, it may be determined that congestion has occurred.

Depending on whether congestion occurs in the session management node determined in step S316, the mobility management node may perform a session establishment procedure with a specific session management node or transmit a session rejection message including a back off timer to the terminal device. . If it is confirmed that congestion has occurred in the corresponding session management node, the mobility management node transmits a session rejection message to reject the terminal device's session establishment request (S318). At this time, the session rejection message may include a backoff timer and a reason indicating that the request was rejected due to congestion.

The time value of the backoff timer can be set by the mobility management node based on congestion information received from the session management node. For example, if it is confirmed that congestion has occurred based on congestion information, the backoff timer can be set to a predetermined time, or the backoff timer can be set variably according to the congestion level. The backoff timer may be set in the mobility management node as described above, but it is not necessarily limited to this, and the session management node may directly detect the congestion state, set the backoff timer according to the congestion level, and transmit it along with the congestion information. .

When the terminal device receives a session rejection message from the mobility management node, the backoff timer included in the session rejection message starts and requests registration for the slice for a predetermined period of time until the backoff timer expires. Either wait without doing so, or select a slice type different from the slice whose registration was rejected (S320 and S322).

Specifically, in the case of services where session establishment is essential (i.e., services where registration with a session management node is essential), if a backoff timer is included in the session rejection message, the terminal device may not You will not be able to request registration. Accordingly, the terminal device waits until the backoff timer expires and then transmits a registration request message for the corresponding slice again.

When session establishment is essential, depending on the embodiment, the terminal device may select a slice of a different type from the slice for which registration has been rejected. In this case, the terminal device has information for selecting another slice. Another slice type selected by the terminal device is a preset slice type, for example, may be set as the default slice type or may be set to select the next priority slice according to the priority list for the slice type. . The default slice type may be a slice type to provide minimum essential services, such as emergency calls, for example.

The terminal device transmits a registration request message (including information about the session type and whether session establishment is necessary) for another selected slice type (i.e., a preset slice type) to the network device. According to the terminal device's second registration request, the mobility management node of the corresponding slice in the network device again checks the congestion status of the session management node, and if it is not congested as a result of the confirmation, performs the registration procedure with the session management node.

On the other hand, in the case of a service in which session establishment is optional (i.e., in the case of a service in which registration as a session management node is optional), session establishment during the slice connection process is not essential, so even if a session rejection message is received, another slice is selected. So there is no need to attempt a registration request. Therefore, the terminal device only needs to wait without requesting registration until the backoff timer included in the session rejection message expires.

A terminal device according to an embodiment of the present invention may have a backoff timer for each mobility management node and one or more session management nodes. That is, each slice and service can have one or more backoff timers.

Figure 4 is a flowchart showing a congestion control method of a network device and a terminal device when congestion occurs in a user plane node within a network slice according to an embodiment of the present invention. Figure 5 is a flowchart showing a congestion control method of a network device and a terminal device when congestion occurs in a user plane node within a network slice according to another embodiment of the present invention.

The network device (not shown) of this embodiment includes a plurality of intra-slice mobility management nodes, one or more session management nodes linked to each mobility management node, and one or more user plane nodes (user plane node 1, …, the function of user plane node n) is implemented. For clarity of explanation, Figures 4 and 5 show only a specific session management node that is linked to a mobility management node within a specific slice among a plurality of slices.

The user plane node (UPGW) performs the function of processing user packets. When congestion occurs, the packets cannot be processed and the packets are discarded, thereby lowering the quality of service experienced by the user. To prevent this, when congestion occurs in a user plane node, the session management node selects a user plane node where congestion does not occur and assigns it to the terminal device.

Specifically, since multiple user plane nodes are linked to one session management node, even if congestion occurs in one user plane node, it is possible to prevent congestion from worsening by allocating another user plane node that does not cause congestion to the terminal device. You can.

Referring to FIG. 4, the network device according to this embodiment acquires congestion information from one or more user plane nodes linked to one or more session management nodes within a specific slice (S410). Figure 4 simply shows a case where only user plane node 1 transmits congestion information, but the remaining user plane nodes also transmit congestion information to the session management node.

User plane nodes can detect that congestion has occurred and transmit congestion information to the session management node. Here, the congestion information may indicate the congestion state based on the maximum number of packets that the user plane node can process and the number of packets being processed, or based on the number of discarded packets. Congestion information may include at least one of congestion level and whether congestion occurs.

For example, the congestion level can be expressed as the ratio of the number of packets currently being processed to the maximum number of packets that can be processed, or the ratio of the number of discarded packets to the total number of packets reaching the user plane node, and whether congestion occurs is determined by It can be simply expressed as a bit indicating congestion/non-congestion.

The terminal device selects a specific type of slice according to the service type for network connection (S412), and when session creation is necessary, a session establishment request message for a specific type of session within the selected type of slice is transmitted to the network device (S412). S414). The session establishment request message is delivered to the session management node, and may include information about the requested session type and a flag indicating whether session establishment (i.e., allocation of a session management node) is essential.

The session management node checks the congestion status of one or more user plane nodes linked to a specific session management node within a specific type of slice based on the congestion information according to the session establishment request message received from the terminal device, and checks the congestion status of the users who do not experience congestion. Select a plane node (S416). Figure 4 illustrates a case where user plane node n is selected as a user plane node without congestion.

In step S416, the session management node can check the congestion status by checking the bit or congestion level indicating congestion included in the congestion information. For example, the bit indicating congestion can be defined as 1 for congestion and 0 for non-congestion, and if the bit indicating congestion is 1, it can be determined that congestion has occurred in the corresponding user plane node. Of course, the opposite case is also possible. As another example, if the congestion level (i.e., a numerical value representing the degree of congestion) is greater than or equal to a preset threshold, it may be determined that congestion has occurred.

Depending on the embodiment, if there are a plurality of user plane nodes that are determined not to be congested, the user plane node with the best degree of congestion may be selected by comparing the congestion levels.

The session management node transmits information about the user plane node without congestion selected in step S416 to the base station device (S418), and transmits information about the base station device to the corresponding user plane node (S420) to perform a session establishment procedure. do. The transmission of each information from the session management node to the base station device and the user plane node is not necessarily limited to the time series order as shown in FIG. 4.

Through the session establishment procedure, a user plane tunnel (i.e., session) is created between the terminal device and the user plane node where congestion does not occur, thereby enabling traffic transmission (S422).

Meanwhile, there may be cases where congestion occurs at a specific user plane node when a session has already been established with the user plane node. In this case, the session management node can move the already established session to another user plane node that is not congested without performing a new session establishment procedure. Hereinafter, it will be described in detail with reference to FIG. 5.

Figure 5 illustrates a state in which a session has already been established between user plane node 1 and the terminal device (S510). In this state, if congestion is detected in user plane node 1, user plane node 1 may transmit congestion information indicating at least one of congestion occurrence and congestion level to the session management node (S512).

Based on the acquired congestion information, the session management node may determine another user plane node (e.g., user plane node n) where congestion does not occur in order to move at least some of the sessions of user plane node 1 where congestion occurred (S514) ). For example, check the flag indicating whether congestion has occurred and select a user plane node where congestion has not occurred, or if there are multiple user plane nodes where congestion has not occurred, compare the congestion levels to select the node with the best degree of congestion. You may be able to determine other user plane nodes by selecting them, etc.

In order to move the existing session, the session management node transmits information about the user plane node determined in step S514 and existing session information to the base station device (S516), and transmits information about the base station device and existing session information to the determined user plane node. Thus, the session transfer procedure can be performed (S518). Likewise, steps S516 and S518 are not necessarily limited to the chronological order shown in FIG. 5.

Through the session transfer procedure, the terminal device can transmit traffic by forming a user plane tunnel with a new user plane node where congestion does not occur (S520).

In Figures 2 to 5, each process is described as being executed sequentially, but the process is not necessarily limited to this. In other words, it may be applicable to executing the processes described in FIGS. 2 to 5 by changing or omitting them, or executing one or more processes in parallel, so FIGS. 2 to 5 are not limited to a time-serial order.

The congestion control method of network devices and terminal devices according to the present embodiment described in FIGS. 2 to 5 may be implemented as a program and recorded on a computer-readable recording medium. A computer-readable recording medium on which a program for implementing the congestion control method according to this embodiment is recorded includes all types of recording devices that store data that can be read by a computing system.

The above description is merely an illustrative explanation of the technical idea of the present embodiment, and those skilled in the art will be able to make various modifications and variations without departing from the essential characteristics of the present embodiment. Accordingly, the present embodiments are not intended to limit the technical idea of the present embodiment, but rather to explain it, and the scope of the technical idea of the present embodiment is not limited by these examples. The scope of protection of this embodiment should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of this embodiment.

100: Mobile communication system
110: Network slice
122: Mobility management node
124: Session management node
132: Userplane node

Claims (16)

In a method for a network device to control network congestion in a mobile communication system in which one physical network is divided according to service type and consists of a plurality of slices, which are logical networks,
Obtaining congestion information from mobility management nodes within the plurality of slices;
selecting a specific slice according to a registration request message for a specific type of slice received from the terminal device, and checking the congestion status of the mobility management node within the selected specific slice based on the congestion information; and
Comprising the step of performing a registration procedure with the selected specific slice or transmitting a registration rejection message including a back off timer to the terminal device depending on whether congestion occurs in the mobility management node within the selected specific slice. ,
The congestion information indicates a congestion state based on the ratio of the maximum number of terminal devices that can connect to the mobility management node and the number of terminal devices in a connected state,
One slice among the plurality of slices includes one mobility management node, the one mobility management node is linked to one or more session management nodes in the one slice, and one session management node is in the one slice. A network congestion control method characterized in that it is linked to one or more user plane nodes within the network. delete According to paragraph 1,
The step of checking the congestion state based on the congestion information is,
A network congestion control method characterized by checking a bit indicating congestion or a congestion level included in the congestion information, and determining that congestion has occurred if the bit indicates a congestion state or the congestion level is higher than a preset threshold. In a method for a terminal device to control network congestion in a mobile communication system in which one physical network is divided according to service type and consists of a plurality of slices, which are logical networks,
Selecting a slice type to be connected and transmitting a registration request message for the slice of the selected type to a network device;
Receiving a registration rejection message including a backoff timer due to congestion of a mobility management node in the slice of the selected type from the network device; and
Waiting without requesting registration until the backoff timer expires according to the registration rejection message, or transmitting a registration request message for a preset slice type to the network device,
Congestion of the mobility management node is confirmed based on congestion information,
The congestion information indicates a congestion state based on the ratio of the maximum number of terminal devices that can connect to the mobility management node and the number of terminal devices in a connected state,
One slice among the plurality of slices includes one mobility management node, the one mobility management node is linked to one or more session management nodes in the one slice, and one session management node is in the one slice. A network congestion control method characterized in that it is linked to one or more user plane nodes within the network. According to clause 4,
A network congestion control method, characterized in that the preset slice type is determined based on the priorities of slice types for which the terminal device requests registration. In a method for a network device to control network congestion in a mobile communication system in which one physical network is divided according to service type and consists of a plurality of slices, which are logical networks,
Obtaining congestion information from one or more session management nodes in each slice;
Receiving a session establishment request message for a specific type of session within a specific type of slice from a terminal device;
selecting a specific session management node within the specific type of slice according to the session establishment request message, and checking a congestion state of the selected specific session management node based on the congestion information; and
Depending on whether congestion occurs in the selected specific session management node, performing a session establishment procedure with the specific session management node, or transmitting a session rejection message including a back off timer to the terminal device; ,
The congestion information indicates a congestion state based on the ratio of the maximum number of sessions that the session management node can manage and the number of sessions being managed,
One slice among the plurality of slices includes one mobility management node, the one mobility management node is linked to one or more session management nodes in the one slice, and one session management node is in the one slice. A network congestion control method characterized in that it is linked to one or more user plane nodes within the network. delete According to clause 6,
The step of checking the congestion state based on the congestion information is,
A network congestion control method characterized by checking a bit indicating congestion or a congestion level included in the congestion information, and determining that congestion has occurred if the bit indicates a congestion state or the congestion level is higher than a preset threshold. According to clause 6,
A network congestion control method, wherein the session establishment request message includes a flag indicating whether session establishment is essential. In a method for a terminal device to control network congestion in a mobile communication system in which one physical network is divided according to service type and consists of a plurality of slices, which are logical networks,
Transmitting a session establishment request message for a specific type of session within a specific type of slice to a network device;
Receiving a session rejection message including a backoff timer from the network device due to congestion of a specific session management node in a specific type of slice selected according to the session establishment request message; and
Waiting without requesting registration for the specific type of slice until the backoff timer expires according to the session rejection message, or transmitting a registration request message for a preset slice type to the network device,
Congestion of the session management node is confirmed based on congestion information,
The congestion information indicates a congestion state based on the ratio of the maximum number of sessions that the session management node can manage and the number of sessions being managed,
One slice among the plurality of slices includes one mobility management node, the one mobility management node is linked to one or more session management nodes in the one slice, and one session management node is in the one slice. A network congestion control method characterized in that it is linked to one or more user plane nodes within the network. According to clause 10,
A network congestion control method, characterized in that the preset slice type is determined based on the priorities of slice types for which the terminal device requests registration. In a method for a network device to control network congestion in a mobile communication system in which one physical network is divided according to service type and consists of a plurality of slices, which are logical networks,
Obtaining congestion information from one or more user plane nodes linked to one or more session management nodes within a specific slice;
Receiving a session establishment request message for a specific type of session within a specific type of slice from a terminal device;
Checking the congestion status of one or more user plane nodes interoperating with a specific session management node according to the session establishment request message based on the congestion information, and selecting a user plane node in which congestion does not occur; and
Transmitting information about the selected user plane node to a base station device and transmitting information about the base station device to the selected user plane node to perform a session establishment procedure,
The congestion information indicates a congestion state based on the ratio of the total number of packets arriving at the user plane node and the number of discarded packets,
One slice among the plurality of slices includes one mobility management node, the one mobility management node is linked to one or more session management nodes in the one slice, and one session management node is in the one slice. A network congestion control method characterized in that it is linked to one or more user plane nodes in the network. According to clause 12,
A network congestion control method, wherein the congestion information indicates a congestion state based on a ratio of the maximum number of packets that the user plane node can process and the number of packets being processed. According to clause 12,
The step of checking the congestion state based on the congestion information is,
A network congestion control method characterized by checking a bit indicating congestion or a congestion level included in the congestion information, and determining that congestion has occurred if the bit indicates a congestion state or the congestion level is higher than a preset threshold. According to clause 12,
A network congestion control method, wherein the session establishment request message includes a flag indicating whether session establishment is essential. According to clause 12,
Obtaining congestion information indicating at least one of congestion occurrence and congestion level from a user plane node where a session is established with the terminal device;
Based on the congestion information, determining another user plane node where congestion does not occur in order to move at least some of the sessions of the user plane node where congestion occurs; and
Transmitting information about the determined user plane node and existing session information to the base station device and transmitting the information about the base station device and the existing session information to the determined user plane node to perform a session transfer procedure.
A network congestion control method further comprising:

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