KR20180107763A - Method for user traffic connection management - Google Patents

Abstract

In a wireless access network connected to user equipment (UE), when the inactivity of some of a plurality of PDU sessions established in the UE is detected, a wireless resource of the detected PDU sessions is released. Then, information regarding the detected PDU sessions is deleted from context information of the UE. An objective of the present invention is to provide a method for user traffic connection management enabling inactivation control for each PDU session in an N2 release procedure for efficient resource management of wireless and network.

Description

METHOD FOR USER TRAFFIC CONNECTION MANAGEMENT [0002]

The present invention relates to a method for managing user traffic connection, and more particularly, to a method of managing user traffic connection for managing user traffic connection between a user equipment and a user plane function of a fifth generation mobile communication network.

In a fifth generation network, there is an N2 Release procedure to save wireless and network resources. This is similar to the S1 release procedure in the fourth generation LTE (Long Term Evolution). The access and mobility management function (AMF) transitions from the CM (Connection Management) -connection state to the CM-idle state through the N2 release procedure and the RAN (Radio Access Network) All UE Context information is erased. At the same time, the N2 signaling connection between the RAN node and the AMF is terminated. Also, the user traffic connection between the terminal and UPF (User Plane Function) is broken. At this time, PDU (Session Data Unit) session information is maintained in the UE, AMF, and SMF (Session Management Function) for fast recovery in the case of service retry. By doing so, services are provided quickly while saving wireless and network resources.

The N2 release procedure contributes much in terms of saving and managing wireless and network resources. The UE and the AMF in the CM-IDLE state through the N2 release procedure recover all the signaling connection and the user plane connection (UP connection) that were released through the service request procedure.

Meanwhile, in the recent 3GPP TS 23.501 standard document, in order to more efficiently manage the resource, in the process of activating the PDU session through the service request after releasing N2, all the PDU sessions of the corresponding UE are unconditionally activated, The definition of "selective activation of UP connection of existing PDU session" that activates the session is added to the definition. This is because it is a waste of resources that a UE having a plurality of PDU sessions must activate all PDU sessions in order to use one PDU session.

Similar to the selective activation of user traffic connections, selective deactivation is also required, since only one PDU session with multiple PDU sessions is used and N2 is released even if no other PDU sessions are used And there is no traffic in all PDU sessions including the last PDU session, N2 release due to user inactivity occurs. This is also a waste of wireless and network resources. However, the current standard specifies only the deactivation of the user plane connection on a per-terminal basis via the N2 release, and there is no way to deactivate the user plane connection per PDU session.

A problem to be solved by the present invention is to provide a user traffic connection management method for enabling inactivation control for each PDU session in the N2 release procedure for efficient resource management of wireless and network.

According to one embodiment of the present invention, a method of managing user traffic connections in a radio access network connected to a User Equipment (UE) is provided. The method of managing a user traffic connection includes releasing a radio resource of a detected PDU session when inactivity of a PDU session is detected among a plurality of PDU sessions established in the UE, Lt; RTI ID = 0.0 > a < / RTI >

According to the present invention, it is possible to easily provide a function of deactivating a user plane connection in units of PDU sessions in the 3GPP 5th generation system architecture, and to enable efficient resource management of wireless and networks. And can also provide selective deactivation of the user plane connection assigned to the terminal without major changes to the existing N2 release procedure.

1 is a diagram illustrating a fifth generation network system to which the present invention is applied.
2 is a diagram illustrating a N2 release procedure in the fifth generation network system shown in FIG.
3 is a diagram illustrating a procedure for selectively inactivating a user traffic connection due to a cause of a RAN-initiated PDU session inactivity according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification and claims, when a section is referred to as "including " an element, it is understood that it does not exclude other elements, but may include other elements, unless specifically stated otherwise.

Now, a user traffic connection management method according to an embodiment of the present invention will be described in detail with reference to the drawings.

1 is a diagram illustrating a fifth generation network system to which the present invention is applied.

Referring to FIG. 1, a fifth generation network system architecture may include various components (i.e., network function (NF)). In FIG. 1, an authentication server function (AUSF: An Access and Mobility Management Function (AMF) 14, a Session Management Function (SMF) 15, a Policy Control Function (PCF) An application function (AF) 17, a unified data management (UDM) 19, a data network (DN) 20, a user plane function (UPF) A Plane Function 13, a (Radio) Access Network (R) AN Access Network 12 and a User Equipment (UE) 11.

Each NF supports the following functions.

The AUSF 18 stores data for authentication of the UE 11.

The AMF 14 provides a function for UE-based access and mobility management, and can be basically connected to one AMF per UE. Some or all functions of the AMF may be supported within a single instance of an AMF.

The DN 20 may be, for example, an operator service, an Internet connection or a third party service. The DN 20 transmits a downlink protocol data unit (PDU) to the UPF 13 or receives a PDU transmitted from the UE 11 from the UPF 13.

The PCF 16 receives information on the packet flow from the application server and provides functions for determining policies such as mobility management and session management.

The SMF 15 provides a session management function and can be managed by different SMFs 15 for each session when the UE 11 has a plurality of sessions. Some or all of the functions of the SMF 15 may be supported in a single instance of one SMF 15. [

The UDM 19 stores user subscription data, policy data, and the like. The UDM 19 includes two parts: an application front end (FE) and a user data repository (UDR).

The UPF 13 delivers the downlink PDU received from the DN 20 to the UE 11 via the (R) AN 12 and from the UE 11 via the (R) AN 12 And transmits an uplink PDU to the DN 20.

The AF 17 may be configured to support the functions of the 3GPP core network 17 to support service provisioning (e.g., support for application impact on traffic routing, network capability exposure access, interworking with the policy framework for policy control, Lt; / RTI >

(R) AN 12 supports both evolved Evolved E-UTRA (Evolved E-UTRA) and new radio access technology (NR) (eg, gNB), an evolutionary version of fourth generation wireless access technology ≪ / RTI >

UE 11 refers to a user equipment. The user equipment may be referred to as a terminal, a mobile equipment (ME), a mobile station (MS), or the like. Further, the user device may be a portable device such as a notebook computer, a mobile phone, a PDA (Personal Digital Assistant), a smart phone, a multimedia device, or the like, or a portable device such as a PC (Personal Computer) or a vehicle-mounted device.

In FIG. 1, unstructured data storage network function (UDSF), structured data storage network function (SDSF), network exposure function (NEF) ) And an NF Repository Function (NRF) are not shown, but all of the NFs shown in FIG. 1 can perform interoperability with UDSF, NEF, and NRF as needed.

If the existing LTE system was an entity-based architecture, the 5th generation network system was designed as a logical functional unit in consideration of virtualization, etc., and the control plane (CP) and user plane (UP) And the principle of minimizing the dependency of an access network (AN) and a core network (CN). The AMF 14 and the SMF 15 use the existing MME (Mobility Management Entity) functions as a function of CM (Connection Management), RM (Registration Management) and MM (Mobility Management) It can be said that it has been modularized by function. The conventional S-GW and P-GW are unified into one UPF 13, and the UDM 19 can be regarded as an extension of the existing HSS (Home Subscriber Server).

The N1 interface between the UE 11 and the AMF 14 can be regarded as a NAS (Non Access Stratum) interface of the existing LTE system and the N4 interface between the UPF 13 and the SMF 15 can be regarded as a non- And corresponds to the GTP (GPRS Tunneling Protocol) -C interface of S11 and S5 of the existing LTE system. The N2 interface between the RAN 12 and the AMF 14 can be regarded as S1AP of the LTE system and the N3 interface between the RAN 12 and the UPF 13 corresponds to S1-U.

2 is a diagram illustrating a N2 release procedure in the fifth generation network system shown in FIG.

Referring to FIG. 2, one UE 11 in the 5th generation network can generate a plurality of PDU sessions (PDU session 1 to PDU session N), and each PDU session (PDU session 1 to PDU session N) And assigns a unique PDU session ID in one UE 11 to distinguish each PDU session (PDU session 1 to PDU session N).

A signaling connection (radio bearer and N2 signaling connection) capable of NAS signaling is established between the UE 11 and the AMF 14 before the N2 cancellation procedure is established and the UE 11 is activated with one or more PDU sessions active. UP connection between the UPF 13 and the UPF 13 is established.

The cause of the N2 release procedure can be broadly divided into RAN initiated or AMF initiation. RAN initiation causes include Operation and Management Intervention (O & M), Unspecified Failure, User Inactivity and Repeated RRC Signaling Integrity Check Failure. Authentication failure, deregistration, and the like are the causes of AMF initiation.

The N2 release procedure by the user inactivity associated with the embodiment of the present invention will be described.

The RAN 12 periodically transmits an RRC Connection Release message to the UE 11 when data traffic is not transmitted through the active PDU session of the corresponding UE 11 for a predetermined time, (S202). ≪ / RTI > Then, the RAN 12 transmits an N2 UE Context Release Request message including cause (Cause: User Inactivity) to the AMF 14 (S204).

The AMF 14 having received the N2 UE Context Release Request message transmits the Subscriber Permanent Identifier (SUPI), which is a unique identifier of the corresponding UE 11, to one or more SMFs 15 to which the corresponding UE 11 belongs. ) To request the UE 11 to release the N3 UP connection (S206). Then, the SMF 15 sends an N4 message including the PDU session ID to the UPF 13 to which the PDU session of the corresponding UE 11 is connected and requests deletion of the RAN tunnel information allocated to the corresponding PDU session (S208).

The UPF 13 cancels the N3 tunnel because it deletes the RAN tunnel of the specific PDU session of the requested UE 11 and transmits the N4 Response message to the SMF 15 in operation S210.

The SMF 15 having received the N4 Response message transmits the N11 Response message to the AMF 14 in response to the N11 tunnel release message in step S212.

After receiving the N11 Response message, the AMF 14 transmits an N2 UE Context Release Command message to the RAN 12 to delete the N2 signaling connection (S214). At this time, the AMF 14 includes the cause (Cause: PDU session inactivity) received in step S204 in the N2 UE Context Release Command message.

The RAN 12 having received the N2 UE Context Release Command message transmits an RRC Connection Release message to the UE 11 in step S202 if the radio resource for the UE 11 has not been deleted And then transmits an N2 UE Context Release Complete message to the AMF 14 in step S218. Thereafter, the RAN 12 deletes all the context information of the corresponding UE 11 and cancels the signaling connection of the AMF 14 as well.

The AMF 14 also releases the RAN tunnel information and the N2 signaling connection of the corresponding UE 11 after receiving the N2 UE Context Release Complete message.

When the steps S204 to S218 are completed, both the signaling connection between the UE 11 and the AMF 14 and the active UP connection between the UE 11 and the UPF 13 are released (S220).

The UE 11 and the AMF 14 transitioning to the CM-IDLE state through the N2 release procedure can recover all signaling connections and UP connections that were released through the service request procedure.

In order to perform more efficient resource management, after the N2 is released, in the process of activating the PDU session through the service request procedure, all the PDU sessions of the corresponding UE 11 are unconditionally activated and the PDU session can be partially activated if necessary . Also, selective deactivation is required, similar to selective activation of user traffic connections. If N2 release does not occur and there is no traffic in all PDU sessions including the last PDU session even if other PDU sessions are not used even if only one PDU session of UEs 11 having a plurality of PDU sessions is used, N2 release due to activity occurs. This is also a waste of wireless and network resources. Therefore, in the embodiment of the present invention, a method for deactivating UP connection per PDU session is proposed.

3 is a diagram illustrating a procedure for selectively inactivating a user traffic connection due to a cause of a RAN-initiated PDU session inactivity according to an embodiment of the present invention.

3, a signaling connection enabling NAS signaling is established between the UE 11 and the AMF 14 and an UP connection is established between the UE 11 and the UPF 13 in the active state of one or more PDU sessions. Is set.

2, when inactivity of all the PDU sessions (PDU session 1 to PDU session N) of the UE 11 is detected, the corresponding UE 11 In the embodiment of the present invention, when inactivity of some PDU sessions is detected, only the radio resources of the detected PDU session of the corresponding UE 11 are released, so that the UE 11 and the RAN AN-specific resource modification process is performed between the base station and the base station (S302). The AN-specific resource modification process can be done, for example, via an RRC connection reset message.

The RAN 12 transmits an N2 UE Context Release Request message including the PDU session inactivity and the PDU session ID (s) that need to release the user traffic connection to the AMF 14 (S304).

The AMF 14 having received the N2 UE Context Release Request message recognizes that the cause is a PDU session inactivity and recognizes that the UE 11 has received at least one SMF 15 (Step S306), and transmits the N11 message including the SUPI of the UE 11 and the PDU session ID (s) received from the RAN 12 to the N3 UP connection of the corresponding PDU session.

Upon receiving the N11 message requesting the deletion of the N3 UP connection, the SMF 15 sends an N4 message to the UPF 13 to which the deletion request of the corresponding PDU session of the corresponding UE 11 is connected to request deletion of the RAN tunnel information (S308) . Then, the UPF 13 cancels the R3 tunnel of the specific PDU session of the requested UE 11, thus releasing the N3 tunnel and transmitting the N4 response message to the SMF 15 (S310).

The SMF 15 having received the N4 response message transmits the N11 response message to the AMF 14 in response to the N11 message together with the N3 release result (S312).

The AMF 14 that has received the N11 response message from the SMF 15 transmits the N2 terminal context to delete the DRB (Data Radio Bearer) which is the radio resource of the corresponding PDU session (s) between the UE 11 and the RAN 12 The AMF 14 transmits a N2 UE Context Command message to the RAN 12 at step S314. At this time, the AMF 14 transmits a N2 UE Context Release Request message to the RAN 12 (Cause: PDU session inactivity) To the N2 UE Context Release Command message.

Upon receiving the N2 UE Context Release Command message, the RAN 12, if the radio resource for the specific PDU session of the corresponding UE 11 has not been released in the AN-specific resource modification procedure, The DRB of the specific PDU session (s) of the UE is released through the resource reconfiguration procedure (RRC Connect Reconfiguration) (S316), and the N2 UE Context Release Command message is transmitted to the AMF 14 in response to the N2 UE Context Release Command message. And transmits an N2 UE Context Release Complete message (S318).

Then, the RAN 12 deletes all the information on the specific PDU session (s), including the RAN tunnel information of the specific PDU session (s), from the context information of the UE 11.

The AMF 14 that has received the N2 UE Context Release Complete message also deletes only the information of the specific PDU session (s) of the corresponding UE 11.

3, the DRB of the specific PDU session (s) of the UE 11 is released and all the N3 tunnels with the UPF 13 are also deleted. I. E., All user traffic connections to the particular PDU session (s). But retains the N2 signaling connection between the RAN 12 and the AMF 14 for the NAS signaling of the other active PDU session (s) without releasing it.

The AMF 14 also maintains the N2 signaling connection without releasing it. 2, the UE 11 is disabled in units of UE, so that all the radio resources of the corresponding UE 11 between the UE 11 and the RAN 12 are deactivated, The bearer is released and the N2 signaling connection of the UE 11 and the user traffic connection of N3 are released.

As described above, in the embodiment of the present invention, since the active PDU session of the corresponding UE 11 remains after the process of selectively deactivating the user traffic connection is completed, the signaling connection between the UE 11 and the AMF 14 The UP connection between the UE 11 and the UPF 13 remains. On the other hand, in the case of releasing the N2 in FIG. 2, since the UE is released in units of UE, when the procedure is completed, there is no remaining signaling connection and UP connection.

Meanwhile, in the embodiment of the present invention, the procedure of selectively deactivating the user traffic with the 'PDU session inactivity' by the RAN-initiation has been described. However, in the AMF 14 or the SMF 15, If necessary, a selective deactivation procedure by AMF-initiated or SMF-initiated with a specific cause (e.g., 'PDU session connection release') may be performed. In this case, it is possible to start at step S306 or step S308 instead of starting at step S304 shown in FIG. 3, and the subsequent procedure is the same as the procedure of FIG.

Also, detection of PDU session inactivity may be performed in the UPF 13 rather than in the RAN 12. That is, the RAN 12 detects PDU session inactivity and sends an N2 Context Release Request message to the AMF 14 including the cause and the corresponding PDU session ID (s) to disable the UP connection UPF 13 may detect PDU session inactivity and request N3 release via N4 message to SMF 15 including cause and corresponding PDU session ID (s). Then, the SMF 15 becomes a subject and can selectively disable the N3 UP connection per PDU session. At this time, the procedures shown in FIG. 3 can be slightly modified by the same concept.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (1)

CLAIMS 1. A method for managing user traffic connections in a wireless access network connected to a User Equipment (UE)
Releasing radio resources of some detected PDU sessions if inactivity of some of the plurality of PDU sessions established in the UE is detected, and
Deleting information on the partial PDU session from context information of the UE
The method comprising the steps of:

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