WO2022001473A1

WO2022001473A1 - User plane function switching method and apparatus supporting ultra-reliable low-latency communication

Info

Publication number: WO2022001473A1
Application number: PCT/CN2021/095270
Authority: WO
Inventors: 唐伟杰; 阮帮秋
Original assignee: 中兴通讯股份有限公司
Priority date: 2020-06-28
Filing date: 2021-05-21
Publication date: 2022-01-06
Also published as: CN113852992A

Abstract

Provided in the embodiments of the present application are a user plane function switching method and apparatus supporting ultra-reliable low-latency communication. The method comprises: according to a session establishment request of a UE, establishing a first UPF for local offloading; according to location information, slice information and a local offloading rule, establishing a second UPF for local offloading; sending a session update message to an SMF, with the session update message comprising deployment information of the first UPF and the second UPF; receiving a session update response message sent by the SMF, with the session update response message comprising N4 information of the second UPF; switching to the second UPF according to the session update response message; and when a latency deletion timer expires or no traffic passes through the first UPF within a preset time period, releasing the first UPF.

Description

User plane function switching method and device supporting ultra-reliable and low-latency communication

technical field

The embodiments of the present application relate to, but are not limited to, the field of mobile communications, and specifically relate to, but are not limited to, a method and apparatus for switching user plane functions that support ultra-reliable and low-latency communication.

Background technique

The fifth generation (5th Generation, 5G) communication system consists of several network functions (Network Function, NF). Among them, the session management function (Session Management Function, SMF) is mainly used to manage the packet data unit (Packet Data Unit, PDU) session of the user terminal (User Equipment, UE), and formulate a package for the user plane function (User Plane Function, UPF). Detection and forwarding rules, etc. In the process of UE moving, when the original SMF cannot provide services, an intermediate session management function (I-SMF) needs to be inserted. When supporting local offloading, the I-SMF is responsible for selecting and managing branching points (Branching Point, BP) or uplink classifier (Uplink Classifier, ULCL) and PDU Session Anchor (PDU Session Anchor, PSA).

In the ultra-reliable low-latency communication (Ultra-Reliable Low-Latency Communication, URLLC) slicing scenario, it is necessary to perform UPF-related operations while maintaining service data continuity. However, in the related art, there is no implementation solution for how to maintain service continuity when the UPF managed by the I-SMF changes in the URLLC slicing scenario.

SUMMARY OF THE INVENTION

The method and device for switching user plane functions that support ultra-reliable and low-latency communication, the network element, and the computer-readable storage medium provided by the embodiments of the present application are used to implement the URLLC slicing scenario, when the UPF managed by the I-SMF changes, the business continuity.

In order to solve the above technical problems, the embodiment of the present application provides a user plane function switching method supporting ultra-reliable and low-latency communication, which is applied to the intermediate session management function I-SMF, including: establishing a local offload first according to a session establishment request of the UE. UPF; establish a local offloading second UPF according to the location information, slice information and local offloading rules; send a session update message to the SMF, where the session update message includes the deployment information of the first UPF and the second UPF; receive a session update response message sent by the SMF, The session update response message includes the N4 information of the second UPF; switches to the second UPF according to the session update response message; when the delay deletion timer expires or the first UPF has no traffic within a preset time period, the first UPF is released.

An embodiment of the present application provides a user plane function switching method supporting ultra-reliable and low-latency communication, which is applied to a session management function SMF, including: receiving a session update message sent by an I-SMF, where the session update message includes a first UPF and a second UPF. Deployment information of the UPF; determine N4 information of the second UPF according to the session update message; send a session update response message to the I-SMF, where the session update response message includes the N4 information of the second UPF.

An embodiment of the present application provides a user plane function switching device that supports ultra-reliable and low-latency communication, including: a processing module configured to establish a local offload first UPF according to a session establishment request of a UE, and according to location information, slice information and local offload The rules establish a local offloading of the second UPF; the sending module is configured to send a session update message to the SMF, where the session update message includes the deployment information of the first UPF and the second UPF; the receiving module is configured to receive a session update response message sent by the SMF, the session update message The update response message includes the N4 information of the second UPF; the switching module is used for switching to the second UPF according to the session update response message; the release module is used for the first UPF when the delay deletion timer expires or no traffic passes through the first UPF within a preset time period , release the first UPF.

An embodiment of the present application provides a user plane function switching device that supports ultra-reliable and low-latency communication, including: a receiving module configured to receive a session update message sent by an I-SMF, where the session update message includes a first UPF and a second UPF. deployment information; a processing module for determining N4 information of the second UPF according to the session update message; a sending module for sending a session update response message to the I-SMF, where the session update response message includes the N4 information of the second UPF.

An embodiment of the present application provides a network element, including a processor, a memory, and a communication bus; the communication bus is used to implement connection and communication between the processor and the memory; the processor is used to execute one or more computer programs stored in the memory to The steps of implementing any one of the above-mentioned methods for switching user plane functions that support ultra-reliable and low-latency communication.

Embodiments of the present application provide a computer-readable storage medium, where one or more computer programs are stored in the computer-readable storage medium, and the one or more computer programs can be executed by one or more processors to implement any of the above The steps of the user plane function switching method supporting ultra-reliable and low-latency communication described above.

Other features and corresponding beneficial effects of the present application are described in later parts of the specification, and it should be understood that at least some of the beneficial effects will become apparent from the description in the specification of the present application.

Description of drawings

FIG. 1 is a schematic diagram of an architecture of a 5G communication system with I-SMF according to an embodiment.

FIG. 2 is a schematic structural diagram of an I-SMF supporting local offload provided by an embodiment.

FIG. 3A is a schematic structural diagram of a UPF transformation managed by an SMF according to an embodiment.

FIG. 3B is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 3A according to an embodiment.

FIG. 4 is a schematic flowchart of a UPF switching method supporting URLLC according to an embodiment.

FIG. 5A is a schematic diagram of the architecture of the local offload anchor point transformation of the I-SMF management provided by an embodiment.

FIG. 5B is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 5A according to an embodiment.

FIG. 5C is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 5A according to another embodiment.

FIG. 6A is a schematic structural diagram of a local distribution point managed by an I-SMF according to an embodiment.

FIG. 6B is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 6A according to an embodiment.

FIG. 7A is a schematic structural diagram of a local offloading point and a local offloading anchor point managed by an I-SMF according to an embodiment.

FIG. 7B is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 7A according to an embodiment.

FIG. 7C is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 7A according to another embodiment.

FIG. 8A is a schematic structural diagram of a UPF switching apparatus supporting URLLC according to an embodiment.

FIG. 8B is a schematic structural diagram of a UPF switching apparatus supporting URLLC according to another embodiment.

FIG. 9 is a schematic structural diagram of a network element provided by an embodiment.

detailed description

In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the embodiments of the present application will be described in further detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application.

FIG. 1 is a schematic diagram of an architecture of a 5G communication system with I-SMF according to an embodiment. As shown in Figure 1, the 5G communication system may include the following NFs: Access Management Function (AMF), Session Management Function (SMF), Intermediate Session Management Function (I-SMF) ), User Plane Function (UPF), Unified Data Management (UDM), Policy Control Function (PCF), NF Repository Function (NRF) and Billing Function (Charging Function, CHF).

Among them, the connection of the user plane is from UE to Radio Access Network (RAN) to UPF (I-SMF) to UPF (SMF), and the connection of control plane is from UE to RAN to AMF to I-SMF to SMF, The control plane and user plane adopt a separate architecture. I-SMF and SMF are selected by AMF, and UPF is selected and managed by SMF. The I-SMF uses the Packet Forwarding Control Protocol (PFCP) to communicate with the UPF.

FIG. 2 is a schematic structural diagram of an I-SMF supporting local offload provided by an embodiment. As shown in Figure 2, the I-SMF is responsible for selecting and managing the branch point BP or ULCL, and the additional PDU session anchor PSA1. The home anchor PSA0 is managed by the SMF, and the N4 information of the PSA1 is required by the protocol to be managed by the SMF.

FIG. 3A is a schematic structural diagram of a UPF transformation managed by an SMF according to an embodiment. The SMF first makes a decision based on the UE's location and the Data Network Access Identifier (DNAI) list, and establishes the S-ULCL and PSA1 local offload UPF. When UE location or service changes, SMF re-selects UPF and establishes T-ULCL and PSA2 local offload UPF. In the URLLC slicing scenario, the continuity of service data needs to be maintained, and data channels need to be established for S-ULCL and T-ULCL.

FIG. 3B is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 3A according to an embodiment. As shown in Figure 3B, the method may include the following steps.

Step 401, the UE initiates a session establishment request to trigger the establishment of a PDU session. The SMF establishes a local offload point Source ULCL, a local offload anchor point Source UPF PSA1, and a home anchor point UPFPSA0.

Step 402: Due to the change of the UE location or the update of the control policy of the PCF (including the local offload rule), the SMF is triggered to perform UPF re-selection according to the location information, slice information and the local offload rule, resulting in the local offload point and the local offload anchor managed by the SMF. point changes.

Step 403: The SMF establishes a new local offload point Target ULCL according to the result selected by the UPF.

Step 404, the SMF updates the Source ULCL, and opens up the N9 tunnel information between the Source ULCL and the Target ULCL, so as to ensure data service continuity.

Step 405, the SMF updates the home anchor point UPF PSA0, and updates the downlink data to the Target ULCL.

Step 406, the SMF establishes a new local shunt anchor point Target UPF PSA2 according to the result of the UPF selection.

Step 407, the SMF updates the N3 tunnel information of the RAN to the Target ULCL.

Step 409, the SMF notifies the AF to update the DNAI.

Step 410, the SMF sets the PSA1 delay deletion timer and detects the data packet of the PSA1.

Step 411: When the waiting timer expires, or there is no traffic in PSA1 for a certain period of time, the SMF deletes PSA1.

Step 412, the SMF deletes the Source ULCL.

In this embodiment, due to changes in UE location or service, some rules that trigger SMF control are changed, and UPF re-selection is performed. Under the ultra-reliability and low-latency requirements of the URLLC slicing scenario, in order to maintain the continuity of service data, Source UL CL and Target UL CL need to establish a data channel, and Source UPF PSA1 needs to be kept until there are no service data packets before it can be deleted. In the URLLC slicing scenario, changing and deleting UPF cannot be performed immediately. UPF-related operations need to be performed while maintaining service data continuity. Usually, multiple stages are required to finally change to the new offload ULCL and offload anchor point.

In order to realize the URLLC slicing scenario, when the UPF managed by the I-SMF changes, the continuity of service data is maintained. The embodiment of the present application provides a UPF switching method supporting URLLC, which is applied to I-SMF. Referring to FIG. 4 , the method may include the following steps.

S101. Establish a local offload first UPF according to a session establishment request of the UE.

S102. Establish a second UPF for local offloading according to the location information, the slice information and the local offloading rule.

S103. Send a session update message to the SMF, where the session update message includes deployment information of the first UPF and the second UPF.

S104. Receive a session update response message sent by the SMF, where the session update response message includes N4 information of the second UPF.

S105. Switch to the second UPF according to the session update response message.

S106. Release the first UPF when the delayed deletion timer expires or when no traffic passes through the first UPF within a preset time period.

The UPF switching method supporting URLLC provided in this embodiment realizes that in the URLLC slicing scenario, when the UPF managed by the I-SMF changes, service continuity is maintained.

In the architecture where the I-SMF supports local offloading, when the location of the UE changes or the control policy of the PCF such as the local offloading rule is updated, the I-SMF will reselect the UPF according to the UE's location information, slice information and local offloading rules. , which will cause the local offload PDU session anchor point PSA managed by the I-SMF to change, or the offload point ULCL to change, or the PSA and ULCL to change at the same time. The following will describe in detail the UPF switching process supporting URLLC in the above three cases where the UPF changes.

FIG. 5A is a schematic diagram of the architecture of the local offload anchor point transformation of the I-SMF management provided by an embodiment. As shown in Figure 5A, in the scenario where the local offloading of PDU sessions with ULCL and PSA1 with I-SMF has been established, due to the change of the UE location or the update of the control policy of the PCF (including the local offloading rule), the location-dependent I-SMF is triggered. Information, slice information, and local offload rules are reselected by UPF, resulting in the transformation of the local offload anchor point managed by I-SMF from PSA1 to PSA2.

FIG. 5B is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 5A according to an embodiment. In this embodiment, the change of the UPF of the local offload anchor point is managed by the I-SMF, so as to ensure the continuity of the local offload service when the local offload anchor point changes from PSA1 to PSA2. As shown in FIG. 5B , the method provided in this embodiment may include the following steps.

Step 501, the UE initiates a session establishment request to trigger the establishment of a PDU session. The I-SMF establishes the ULCL and the local shunt anchor Source UPF PSA1. SMF establishes the home anchor UPF PSA0.

Step 502: When the location of the UE changes or the control strategy of the PCF is updated (including the local offloading rules), the I-SMF reselects the UPF according to the UE's location information, slice information and local offloading rules, resulting in the local offloading anchor managed by the I-SMF. The point changes from PSA1 to PSA2.

Step 503, the I-SMF establishes a new local shunt UPF PSA2 according to the result of the UPF selection, and the PSA2 at this time has no information related to N4.

Step 504 , the I-SMF notifies the SMF through a session update message, the establishment of PSA2 and the supported DNAI, and the deletion of PSA1 and the supported DANI.

In step 505, the SMF judges that the DNAI has changed according to the message information in step 504, and notifies the AF, and the AF performs corresponding operations.

Step 506, the SMF generates the N4 information and charging information of the PSA2, and carries them to the I-SMF through the session update request message initiated by the network side.

Step 507, the I-SMF initiates a PFCP session establishment request to PSA2, carrying N4 information and charging information, and the downlink traffic is distributed to the ULCL.

Step 508: The I-SMF updates the offload rule of the ULCL, and the new upstream service traffic is offloaded to the local data network (Data Network, DN) through the new PSA2.

Step 509: The I-SMF generates a corresponding detection rule for PSA1 to detect whether PSA1 has no traffic passing through.

Step 510, the I-SMF replies a session update response to the SMF, notifying that the N4 information is successfully installed, but the upstream and downstream traffic of the PSA1 is still smooth. At this time, the uplink and downlink data tunnels from DN to PSA2 to BP/ULCL have been opened.

Step 511, the I-SMF sets the PSA1 delay deletion timer, and releases the PSA1 after the timer expires.

Step 512, when the delay timer of PSA1 expires or the detection rule in step 509 has no traffic for a certain period of time, notify the I-SMF to release PSA1 through the Session Report message of PFCP, the I-SMF notifies the release of PSA1, and PSA1 reports the traffic to the I-SMF .

Step 513, the I-SMF sends a session PDU session update request to the SMF, notifying the SMF that it has been deleted and carrying the traffic report of PSA1, and the SMF reports the traffic to the CHF.

In this embodiment, the I-SMF performs corresponding processing of data service continuity on the change of the local offload anchor point UPF. SMF does not distinguish whether it is URLLC or not, and directly delivers N4 information in the current protocol process, and I-SMF controls the operation sequence of UPF to ensure business continuity; I-SMF manages the changes from PSA1 to PSA2 to ensure PSA1 service traffic Continuity: The traffic detection rule of PSA1 is generated locally by I-SMF. If there is no traffic within a specified time, PSA1 reports to I-SMF. The I-SMF triggers the deletion of PSA1, or the I-SMF sets the PSA1 timeout deletion timer. After the timer expires, the I-SMF triggers the method of deleting the PSA1; after the PSA1 is deleted, the traffic is reported to the SMF, and finally to the CHF.

FIG. 5C is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 5A according to another embodiment. In this embodiment, the SMF is used to manage the change of the UPF of the local offload anchor point, so as to ensure the continuity of the local offload service when the local offload anchor point changes from PSA1 to PSA2. As shown in FIG. 5C , the method provided by this embodiment may include the following steps.

Step 601, the UE initiates a session establishment request and the establishment is completed, the I-SMF establishes the ULCL and the local offload UPF PSA1, and the SMF establishes the home anchor point UPF PSA0.

Step 602, due to UE location change or PCF control policy update (including local offloading rules), I-SMF is triggered to perform UPF re-selection based on location information, slice information and local offloading rules, resulting in local offloading managed by I-SMF. Anchor UPF changes.

Step 603: The I-SMF establishes a new local shunt UPF PSA2 according to the result of the UPF selection, and the PSA2 at this time has no information related to N4.

Step 604 , the I-SMF notifies the SMF through a session update message that PSA2 is established and supported DNAI, and PSA1 is deleted and supported DANI.

In step 605, the SMF judges that the DNAI has changed according to the message information in step 604, and notifies the AF, and the AF performs corresponding operations.

Step 606, the SMF sets the PSA1 delay deletion timer, and releases the PSA1 after the timer expires.

Step 607: SMF generates N4 information and charging information of PSA2, and generates corresponding detection rules for PSA1, detects whether PSA1 has no traffic passing, and carries it to the I-SMF through a session update request message initiated by the network side.

Step 608, the I-SMF initiates a PFCP session establishment request to PSA2, carrying N4 information and charging information, and the downlink traffic is distributed to the ULCL.

In step 609, the I-SMF updates the offload rule of the ULCL, and the new upstream service traffic is offloaded to the local DN through the new PSA2.

Step 610: The I-SMF installs the PSA1 traffic detection rule generated by the installation SMF on the PSA through the N4 update message.

Step 611, the I-SMF replies a session update response to the SMF, notifying that the N4 information is successfully installed, but the upstream and downstream traffic of the PSA1 is still smooth. At this time, the uplink and downlink data tunnels from DN to PSA2 to BP/ULCL have been opened.

Step 612: If the SMF sets the PSA1 delayed deletion timer to expire, the SMF triggers a session update message on the network side to notify the I-SMF to delete the PSA1.

In step 613, the I-SMF notifies the release of the PSA1, and the PSA1 reports the traffic to the I-SMF.

Step 614, the I-SMF sends a session PDU session update response to the SMF, notifying the SMF that it has been deleted and carries the traffic report of PSA1.

Step 615: If there is no timeout in step 612, and the detection rule has no traffic within a certain period of time, the I-SMF is notified to release the PSA1 through the Session Report message of PFCP, the I-SMF notifies the PSA1 to release, and the PSA1 reports the traffic to the I-SMF. The I-SMF sends a session PDU session update request to the SMF, informing the SMF that it has been deleted and carries the traffic report of PSA1, and the SMF reports the traffic to the CHF.

In this embodiment, when the SMF determines that the offload anchor point of the I-SMF changes and the URLLC slice is to be supported, the SMF controls the timing of sending it to the I-SMF, thereby controlling the operation sequence of the UPF to ensure service continuity ;The traffic detection rule of PSA1 is generated by SMF. If there is no traffic within the specified time, PSA1 reports I-SMF, and I-SMF triggers the deletion of PSA1, or SMF sets the PSA1 timeout deletion timer. After the timer expires, SMF Notify the I-SMF to delete PSA1, and the I-SMF executes the method of deleting PSA1; after PSA1 is deleted, it reports the traffic to the SMF, and finally reports it to the CHF.

FIG. 6A is a schematic structural diagram of a local distribution point managed by an I-SMF according to an embodiment. As shown in FIG. 6A , in the scenario where the local offloading of PDU sessions with ULCL and PSA1 with I-SMF has been established, due to UE location change or PCF control policy update (including local offloading rules), I-SMF based on location is triggered Information, slice information and local offloading rules are reselected by UPF, resulting in the transformation of the UPF of the local offloading point managed by the I-SMF from Source ULCL to Target ULCL.

FIG. 6B is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 6A according to an embodiment. In this embodiment, the change of the UPF of the local offload point is managed by the I-SMF, so as to ensure the continuity of the local offload service when the UPF of the local offload point is converted from the Source ULCL to the Target ULCL. As shown in FIG. 6B , the method provided by this embodiment may include the following steps.

Step 701, the UE initiates a session establishment request and the establishment is completed, the I-SMF establishes the ULCL and the local offload UPF PSA1, and the SMF establishes the home anchor point UPF PSA0.

Step 702, due to UE location change or PCF control policy update (including local offloading rules), I-SMF is triggered to perform UPF re-selection based on location information, slice information and local offloading rules, resulting in the offloading point managed by I-SMF. UPF changes.

Step 703: The I-SMF establishes a new shunt UPF Target ULCL according to the result of the UPF selection, and the Target ULCL at this time has no information related to N4.

Step 704: The I-SMF notifies the SMF through a session update message, which carries the N9 tunnel information of the Target ULCL.

Step 705, the SMF updates the home anchor point UPF PSA0, and updates the downlink traffic to the Target ULCL.

In the embodiment of the present application, the I-SMF performs corresponding processing of data service continuity on the change of the local offload anchor point UPF.

Step 706, the SMF sends a session update response message to the I-SMF.

Step 707, the I-SMF initiates a PFCP session establishment request to PSA1, and updates the downlink traffic to the offload Target ULCL.

In step 708, the I-SMF generates a corresponding detection rule for the Source ULCL to detect whether the Source ULCL has no traffic. At this point, the uplink and downlink data tunnels from DN to PSA1 to Target BP/ULCL have been opened.

Step 709, the I-SMF notifies the RAN to update the uplink N3 tunnel information of the RAN.

Step 710, the I-SMF sets the Source ULCL delay deletion timer, and releases the Source ULCL after the timer times out.

Step 711, when the delay timer of the Source ULCL expires or the detection rule of step 708 has no traffic within a certain period of time, notify the I-SMF to release the Source ULCL through the Session Report message of PFCP, and the I-SMF notifies the PSA1 to release.

In this embodiment, the I-SMF controls the change from Source ULCL to Target ULCL, and performs corresponding processing of data service continuity. SMF does not distinguish whether it is URLLC or not, and directly sends N4 information in the current protocol process, and I-SMF controls the operation sequence of UPF to ensure business continuity; I-SMF manages the change from Source ULCL to Target ULCL to ensure that Source ULCL changes to Target ULCL. Continuity of ULCL service traffic: The traffic detection rule of Source ULCL is generated locally through I-SMF. If there is no traffic within a specified time, Source ULCL reports to I-SMF, and I-SMF triggers the method of deleting Source ULCL, or I-SMF setting The Source ULCL time-out delete timer, after the timer expires, the I-SMF triggers the method of deleting the Source ULCL; since the ULCL is deleted, there is no need to report the traffic to the SMF.

FIG. 7A is a schematic structural diagram of a local offloading point and a local offloading anchor point managed by an I-SMF according to an embodiment. As shown in Fig. 7A, in the scenario where the local offloading of PDU sessions with ULCL and PSA1 with I-SMF has been established, due to UE location change or PCF control policy update (including local offloading rules), I-SMF based on location is triggered The UPF information, slice information and local offloading rules are re-selected, resulting in the transformation of the local offload anchor point UPF managed by the I-SMF from PSA1 to PSA2, and the local offload point UPF from Source ULCL to Target ULCL.

FIG. 7B is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 7A according to an embodiment. This embodiment manages the UPF change through the I-SMF to ensure the continuity of the local offload service when the offload point Source ULCL changes to the Target ULCL and the offload anchor point PSA1 changes to PSA2. As shown in FIG. 7B , the method provided by this embodiment may include the following steps.

Step 801, the UE initiates a session establishment request and the establishment is completed, the I-SMF establishes the ULCL and the local offload UPF PSA1, and the SMF establishes the home anchor point UPF PSA0.

Step 802, due to UE location change or PCF control policy update (including local offload rules), I-SMF is triggered to perform UPF re-selection based on location information, slice information and local offload rules, resulting in the offload point managed by I-SMF. UPF changes and local shunt anchor UPF changes.

Step 803: The I-SMF establishes a new shunt UPF Target ULCL according to the result of the UPF selection, and the Target ULCL at this time has no information related to N4.

Step 804, the I-SMF establishes a new local shunt UPF PSA2 according to the result of the UPF selection, and the PSA2 at this time has no information related to N4.

Step 805, the I-SMF updates the Source ULCL, and opens up the N9 tunnel information between the Source ULCL and the Target ULCL, so as to ensure the continuity of the data service.

Step 806, the I-SMF notifies the SMF through a session update message, PSA2 is established and supported DNAI, PSA1 is deleted and supported DANI, and the newly established Target ULCL and new N9 tunnel information.

Step 807, the SMF updates the home anchor point UPF PSA0, and updates the downlink traffic to the Target ULCL.

In step 808, the SMF judges that the DNAI has changed according to the message information in step 806, and notifies the AF, and the AF performs corresponding operations.

Step 809, the SMF generates the N4 information and charging information of PSA2, and the offloading rule of the Target ULCL, and carries it to the I-SMF through the session update request message initiated by the network side.

Step 810, the I-SMF initiates a PFCP session establishment request to PSA2, carrying N4 information and charging information, and the downlink traffic is sent to the Target ULCL.

Step 811, the I-SMF updates the offload rule of the Target ULCL, and the new upstream service traffic is offloaded to the local DN through the new PSA2.

Step 812, the I-SMF notifies the RAN to update the uplink N3 tunnel information of the RAN.

Step 813: The I-SMF generates a corresponding detection rule for PSA1 to detect whether there is no traffic passing through PSA1, and does not need to be delivered to the Source ULCL.

Step 814, the I-SMF replies a session update response to the SMF, notifying that the N4 information installation is successful, but the upstream and downstream traffic of the PSA1 is still smooth. At this point, the uplink and downlink data tunnels from DN to PSA2 to Target BP/ULCL have been opened.

Step 815, the I-SMF sets the PSA1 delay deletion timer, and releases the PSA1 after the timer expires.

Step 816: When the delay timer of PSA1 expires or the detection rule in step 813 has no traffic for a certain period of time, notify the I-SMF to release PSA1 through the Session Report message of PFCP, the I-SMF notifies the release of PSA1, and PSA1 reports the traffic to the I-SMF .

Step 817, the I-SMF sends a session PDU session update request to the SMF, notifying the SMF that it has been deleted and carrying the traffic report of PSA1, and the SMF reports the traffic to the CHF.

In this embodiment, the I-SMF controls the changes from Source ULCL to Target ULCL and from PSA1 to PSA2. SMF does not distinguish whether it is URLLC or not, and directly sends N4 information in the current protocol process, and the I-SMF controls the operation sequence of UPF. , to ensure business continuity; I-SMF manages the changes from Source ULCL to Target ULCL and PSA1 to PSA2 to ensure the continuity of Source ULCL and PSA1 business traffic: Generate traffic detection rules for PSA1 locally through I-SMF, and at a specified time If there is no traffic, PSA1 reports the I-SMF, and the I-SMF triggers the deletion of Source ULCL and PSA1, or the I-SMF sets the Source ULCL and PSA1 timeout deletion timer. After the timer expires, the I-SMF triggers the Source ULCL And the method of deleting PSA1; after PSA1 is deleted, the traffic is reported to SMF, and finally reported to CHF.

FIG. 7C is a schematic flowchart of the UPF switching method supporting URLLC in FIG. 7A according to another embodiment. In this embodiment, the UPF change is managed through the SMF to ensure the continuity of the local offload service when the offload point Source ULCL changes to Target ULCL and the anchor point PSA1 changes to PSA2. As shown in FIG. 7C , the method provided by this embodiment may include the following steps.

Step 901, the UE initiates a session establishment request and the establishment is completed, the I-SMF establishes the ULCL and the local offload UPF PSA1, and the SMF establishes the home anchor point UPF PSA0.

Step 902, due to UE location change or PCF control policy update (including local offload rules), I-SMF is triggered to perform UPF re-selection based on location information, slice information and local offload rules, resulting in the offload point managed by I-SMF. UPF changes and local shunt anchor UPF changes.

Step 903: The I-SMF establishes a new shunt UPF Target ULCL according to the result of the UPF selection, and the Target ULCL at this time has no information related to N4.

Step 904, the I-SMF establishes a new local shunt UPF PSA2 according to the result of the UPF selection, and the PSA2 at this time has no information related to N4.

Step 905, the I-SMF updates the Source ULCL, and opens up the N9 tunnel information between the Source ULCL and the Target ULCL, so as to ensure the continuity of the data service.

Step 906, the I-SMF notifies the SMF through a session update message, PSA2 is established and supported DNAI, PSA1 is deleted and supported DANI, and the newly established Target ULCL and new N9 tunnel information.

Step 907, the SMF updates the home anchor point UPF PSA0, and updates the downlink traffic to the Target ULCL.

In step 908, the SMF judges that the DNAI has changed according to the message information in step 906, and notifies the AF, and the AF performs corresponding operations.

Step 909, the SMF sets the PSA1 delay deletion timer, and releases the PSA1 after the timer expires.

Step 910, SMF generates the N4 information and charging information of PSA2, and generates corresponding detection rules for PSA1, detects whether PSA1 has no traffic passing through, and the shunting rules of Target ULCL, which are carried to the 1 through the session update request message initiated by the network side. -SMF.

Step 911, the I-SMF initiates a PFCP session establishment request to PSA2, carrying N4 information and charging information, and the downlink traffic is sent to the Target ULCL.

Step 912, the I-SMF updates the offload rule of the Target ULCL, and the new upstream service traffic is offloaded to the local DN through the new PSA2.

Step 913, the I-SMF notifies the RAN to update the uplink N3 tunnel information of the RAN.

Step 914: The I-SMF installs the PSA1 traffic detection rule generated by the installation SMF on the PSA1 through the N4 update message.

Step 915, the I-SMF replies a session update response to the SMF, notifying that the N4 information installation is successful, but the upstream and downstream traffic of the PSA1 is still smooth. At this point, the uplink and downlink data tunnels from DN to PSA2 to Target BP/ULCL have been opened.

Step 916: If the SMF sets the PSA1 delay deletion timer to expire, the SMF triggers a session update message on the network side to notify the I-SMF to delete the PSA1.

Step 917, the I-SMF notifies the release of the PSA1, and the PSA1 reports the traffic to the I-SMF.

Step 918, the I-SMF notifies the Soure ULCL release.

Step 919, the I-SMF sends a session PDU session update response to the SMF, notifying the SMF that it has been deleted and carries the traffic report of PSA1.

Step 920. If there is no timeout in step 916, and the detection rule has no traffic within a certain period of time, the I-SMF is notified to release PSA1 through the Session Report message of PFCP, the I-SMF notifies the PSA1 to release, and the PSA1 reports the traffic to the I-SMF; I-SMF notifies Soure ULCL release; I-SMF sends a session PDU session update request to SMF, notifying SMF that it has been deleted and carrying the traffic report of PSA1, and SMF reports traffic to CHF.

In this embodiment, the changes from Source ULCL to Target ULCL and from PSA1 to PSA2 are controlled by the SMF. When the SMF determines that it is the change of the offload anchor point of the I-SMF and the URLLC slice is to be supported, the SMF controls the changes to be sent to the I-SMF. The timing is used to control the operation sequence of UPF to ensure the continuity of the service; the traffic detection rule of PSA1 is generated by SMF. If there is no traffic within a specified time, PSA1 reports to I-SMF, and I-SMF triggers the deletion of Source ULCL and PSA1 , or the SMF sets the PSA1 timeout deletion timer. After the timer expires, the SMF notifies the I-SMF to delete the PSA1, and the I-SMF executes the method of deleting Source ULCL and PSA1; after the PSA1 is deleted, the traffic is reported to the SMF, and finally reported to CHF.

To sum up, the present application implements ultra-reliable and low-latency service continuity support for URLLC slices for the scenario of I-SMF-managed offloading ULCL or offloading anchor UPF changes, which makes up for the I-SMF management in the protocol. The multi-UPF change scenario supports incomplete defects, and completes the local offload deployment and switching of I-SMF with high quality.

This embodiment also provides a network element, as shown in FIG. 9 , which includes a processor 1001 , a memory 1002 and a communication bus 1003 .

The communication bus 1003 is used to realize the connection communication between the processor 1001 and the memory 1002;

The processor 1001 is configured to execute one or more computer programs stored in the memory 1002 to implement at least one step in the user plane function switching method supporting ultra-reliable and low-latency communication provided by any of the foregoing embodiments.

The present embodiments also provide a computer-readable storage medium embodied in any method or technology for storing information, such as computer-readable instructions, data structures, computer program modules, or other data volatile or nonvolatile, removable or non-removable media. Computer-readable storage media include but are not limited to RAM (Random Access Memory, random access memory), ROM (Read-Only Memory, read-only memory), EEPROM (Electrically Erasable Programmable read only memory, electrically erasable programmable read only memory) ), flash memory or other memory technology, CD-ROM (Compact Disc Read-Only Memory), digital versatile disk (DVD) or other optical disk storage, magnetic cartridges, magnetic tape, magnetic disk storage or other magnetic storage devices, Or any other medium that can be used to store the desired information and that can be accessed by a computer.

The computer-readable storage medium in this embodiment may be used to store one or more computer programs, and the stored one or more computer programs may be executed by a processor to implement the ultra-reliable and low-latency support provided by any of the foregoing embodiments. At least one step in a method for switching user plane functions of communication.

It can be seen that those skilled in the art should understand that all or some of the steps in the methods disclosed above, the functional modules/units in the system, and the device can be implemented as software (which can be implemented by computer program codes executable by a computing device). ), firmware, hardware, and their appropriate combination. In hardware embodiments, the division between functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be composed of several physical components Components execute cooperatively. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit .

In addition, communication media typically embodies computer readable instructions, data structures, computer program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and can include any information delivery, as is well known to those of ordinary skill in the art medium. Therefore, the present application is not limited to any particular combination of hardware and software.

The above content is a further detailed description of the embodiments of the present application in conjunction with specific embodiments, and it cannot be considered that the specific implementation of the present application is limited to these descriptions. For those of ordinary skill in the technical field of the present application, without departing from the concept of the present application, some simple deductions or substitutions can be made, which should be regarded as belonging to the protection scope of the present application.

Claims

A user plane function switching method supporting ultra-reliable and low-latency communication is applied to the intermediate session management function I-SMF, including:

Establish a local offload first UPF according to the session establishment request of the UE;

establishing a second UPF for local offloading according to the location information, slice information and local offloading rules;

sending a session update message to the SMF, where the session update message includes deployment information of the first UPF and the second UPF;

receiving a session update response message sent by the SMF, where the session update response message includes the N4 information of the second UPF;

switch to the second UPF according to the session update response message;

The first UPF is released when the delayed deletion timer expires or when no traffic passes through the first UPF within a preset time period.
The method of claim 1, wherein if the first UPF includes a first PSA and the second UPF includes a second PSA, the session update message includes the DNAI supported by the first PSA and the The DNAI supported by the second PSA, the switching to the second UPF according to the session update response message, includes:

Initiating a PFCP session establishment request to the second PSA, where the session establishment request carries the N4 information and charging information of the second PSA;

Update the second PSA to offload downlink service traffic to the ULCL;

The offload rule of the ULCL is updated, and the new upstream service traffic is offloaded to the local DN through the second PSA2.
The method of claim 1, wherein if the first UPF includes a first ULCL and the second UPF includes a second ULCL, the session update message includes N9 tunnel information of the second ULCL, and the The switching to the second UPF according to the session update response message includes:

Initiating a PFCP session establishment request to the local offload anchor, and updating the downlink service traffic to the second ULCL;

Update the uplink N3 tunnel information of the RAN.
The method of claim 1, wherein if the first UPF includes a first PSA and a first ULCL and the second UPF includes a second PSA and a second ULCL, the session update message includes the first The DNAI supported by a PSA, the DNAI supported by the second PSA, and the N9 tunnel information of the second ULCL, the switching to the second UPF according to the session update response message, including:

Initiating a PFCP session establishment request to the second PSA, where the session establishment request carries the N4 information and charging information of the second PSA;

updating the second PSA to offload downlink service traffic to the second ULCL;

Update the offload rule of the second ULCL, and the new upstream service traffic is offloaded to the local DN through the second PSA2;

Update the uplink N3 tunnel information of the RAN.
A user plane function switching method supporting ultra-reliable and low-latency communication, applied to a session management function SMF, includes:

receiving a session update message sent by the I-SMF, where the session update message includes deployment information of the first UPF and the second UPF;

determining the N4 information of the second UPF according to the session update message;

Send a session update response message to the I-SMF, where the session update response message includes the N4 information of the second UPF.
The method of claim 5, wherein the method further comprises:

setting a delayed deletion timer for the first UPF;

generating a detection rule for the first UPF, which is used to detect whether no traffic passes through the first UPF within a preset time period;

When the delayed deletion timer expires or the first UPF has no traffic passing within a preset time period, an indication message is sent to the I-SMF, which is used to instruct the I-SMF to release the first UPF.
A user plane function switching device supporting ultra-reliable and low-latency communication, comprising:

a processing module, configured to establish a local offloading first UPF according to a session establishment request of the UE, and establish a local offloading second UPF according to the location information, slice information and local offloading rules;

a sending module, configured to send a session update message to the SMF, where the session update message includes deployment information of the first UPF and the second UPF;

a receiving module, configured to receive a session update response message sent by the SMF, where the session update response message includes the N4 information of the second UPF;

a switching module, configured to switch to the second UPF according to the session update response message;

A release module, configured to release the first UPF when the delayed deletion timer expires or when the first UPF has no traffic passing through the first UPF within a preset time period.
A user plane function switching device supporting ultra-reliable and low-latency communication, comprising:

a receiving module, configured to receive a session update message sent by the I-SMF, where the session update message includes deployment information of the first UPF and the second UPF;

a processing module, configured to determine the N4 information of the second UPF according to the session update message;

A sending module, configured to send a session update response message to the I-SMF, where the session update response message includes N4 information of the second UPF.
A network element includes a processor, a memory and a communication bus;

The communication bus is used to realize the connection communication between the processor and the memory;

The processor is configured to execute one or more computer programs stored in the memory, so as to implement the steps of the user plane function switching method supporting ultra-reliable and low-latency communication according to any one of claims 1 to 6.
A computer-readable storage medium storing one or more computer programs, the one or more computer programs being executable by one or more processors to realize the invention as claimed in claims 1 to 6 The steps of any one of the user plane function switching methods supporting ultra-reliable and low-latency communication.