Mobile communication system
By introducing access management, session management, and slice control management components in base stations and core networks, the problem of slice control interruption caused by insufficient resources in 5G mobile communication systems is solved, and uninterrupted slice control and PDU session switching are achieved.
Patent Information
- Application Number
- CN202380084943.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-02-15
- Publication Date
- 2025-09-12
AI Technical Summary
In 5G mobile communication systems, when resources on the core network side are insufficient, the target RAN node cannot effectively switch to the alternative slice, resulting in the inability to continue the PDU session and uninterrupted slice control.
By introducing access management, session management and slice control management components between the base station and the core network, the registration and sessions of the slices are managed collaboratively to ensure that switching to alternative slices can be achieved when resources are insufficient, thus achieving uninterrupted slice control.
Even when core network resources are insufficient, it can continue to replace slice control to ensure uninterrupted switching and slice control of PDU sessions.
Smart Images
Figure CN120642424A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a mobile communication system. Background Art
[0002] The fifth generation mobile communication system (5GS) is characterized in that a communication service with communication characteristics suitable for the use case requirements is provided by performing slicing control corresponding to the use case.
[0003] Typically, when UE (User Equipment) initially connects to the network, it requests the network for the desired slice control category (Requested NSSAI (Network Slice Selection Assistance Information)). The network returns the slice control category that can be provided (Allowed NSSAI) based on the request, determines the slice control category, and thereby performs slice control.
[0004] In addition, when the UE moves between RAs (Registration Areas) and performs handover, if it is difficult to provide the first slice control originally enjoyed by the UE due to insufficient resources on the core network side in the RA of the mobile destination, slice control can be continuously provided without interruption by providing an alternative second slice control that the network can provide (for example, refer to non-patent document 1).
[0005] Moreover, according to the regulations of 3GPP (Third Generation Partnership Project), if it is difficult to continue to provide the first slice on the core network side when the UE performs switching, the target RAN (Radio Access Network) node will send a path switching request to the AMF to switch the provision of slice control from the first slice to the second slice.
[0006] Prior art literature
[0007] Non-patent literature
[0008] Non-Patent Document 1: 3GPP TR 38.832 V17.0.0, 2021 Summary of the Invention
[0009] Problems to be solved by the invention
[0010] However, 3GPP does not specify a method for the target RAN node to know that it is difficult to continuously provide the first slice on the core network side.
[0011] Therefore, at present, the target RAN node cannot send the path switching request triggered by the difficulty in continuously providing the first slice on the core network side to the AMF (Access Management Function), the PDU session cannot be switched to the new PDU session in the second slice, and the slice control cannot be continued.
[0012] Therefore, the purpose of one or more methods of the present disclosure is to continue alternative slice control even when it is difficult to provide slice control being provided due to insufficient resources on the core network side, etc.
[0013] Means for solving problems
[0014] The mobile communication system of the first mode of the present disclosure comprises: a first base station; a second base station; an access management unit, which manages the registration of a mobile terminal that establishes a session with the first base station and the second base station to a slice; a session management unit, which manages the session of the mobile terminal in the slice; and a slice control management unit, which manages whether the slice can be controlled, and is characterized in that when the mobile terminal that has established a session in the first slice needs to switch to the second base station, the first base station notifies the access management unit of the occurrence of the switching of the mobile terminal, the access management unit notifies the session management unit of the occurrence of the switching of the mobile terminal, and inquires the slice control management unit whether it can continue the first slice in the second base station and whether it can register to the second slice different from the first slice in the second base station, and the session management unit inquires the slice control management unit whether it can continue the session of the first slice in the second base station and whether it can establish a session of the second slice in the second base station.
[0015] The mobile communication system of the second mode of the present disclosure comprises: a first base station; a second base station; a first access management unit, which manages the registration of a mobile terminal that establishes a session with the first base station to a slice; a second access management unit, which manages the registration of the mobile terminal that establishes a session with the second base station to a slice; a session management unit, which manages the session of the mobile terminal in the slice; and a slice control management unit, which manages whether the slice can be controlled, and is characterized in that when the mobile terminal that has established a session in the first slice needs to switch to the second base station, the first base station switches the mobile terminal's The occurrence of the switch is notified to the first access management unit, the first access management unit notifies the second access management unit of the occurrence of the switch of the mobile terminal, the second access management unit notifies the session management unit of the occurrence of the switch of the mobile terminal, and inquires the slice control management unit whether it can continue the first slice in the second base station and whether it can register to the second slice different from the first slice in the second base station, the session management unit inquires the slice control management unit whether it can continue the session of the first slice in the second base station and whether it can establish the session of the second slice in the second base station.
[0016] Effects of the Invention
[0017] According to one or more aspects of the present disclosure, even when it is difficult to provide slice control that is being provided due to insufficient resources on the core network side, etc., alternative slice control can be continued. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 This is a block diagram schematically showing the configuration of the mobile communication system according to the first embodiment.
[0019] Figure 2 This is a sequence diagram showing the operations in the mobile communication system according to the first embodiment.
[0020] Figure 3 This is a block diagram schematically showing the structure of a mobile communication system according to the second embodiment.
[0021] Figure 4 This is a sequence diagram showing the operations in the mobile communication system according to the second embodiment. DETAILED DESCRIPTION
[0022] Implementation Method 1
[0023] Figure 1 This is a block diagram schematically showing the configuration of mobile communication system 100 according to Embodiment 1.
[0024] In addition, Figure 1, only elements related to this embodiment are shown, and description of other elements is omitted.
[0025] The mobile communication system 100 includes a UE (User Equipment) 110 , a RAN (Radio Access Network) 120 , and a core network 130 .
[0026] UE 110 is a mobile terminal.
[0027] RAN 120 is a network of wireless base stations.
[0028] RAN 120 includes at least a source RAN node 121 to which UE 110 was connected before handover, and a target RAN node 122 to which UE 110 is to be handed over. RAN node 121 is also referred to herein as a source base station or first base station, and target RAN node 122 is also referred to herein as a destination base station or second base station.
[0029] The core network 130 is a 5G core network.
[0030] Part of the functions of the core network 130 includes AMF (Access Management Function) 131 , SMF (Session Management Function) 132 , and NSACF (Network Slice Admission Control Function) 133 .
[0031] AMF 131 is a network access management function. Here, AMF 131 functions as an access management unit that cooperates with NSACF to register the slice type of UE 110 accessing RAN node 121 and target RAN node 122.
[0032] The SMF 132 is a function for managing PDU (Protocol Data Unit) sessions. Here, the SMF 132 functions as a session management unit that determines a slice type when establishing a session with the UE 110 in cooperation with the NSACF.
[0033] The NSACF 133 is a slice control permission management function. Here, the NSACF 133 functions as a slice control management unit that manages whether or not slices of each slice type can be controlled.
[0034] In the first embodiment, when UE 110, which has established a session in the first slice, needs to be handed over to target RAN node 122, RAN node 121 notifies AMF 131 of the occurrence of handover for UE 110. AMF 131 notifies SMF 132 of the occurrence of handover for UE 110 and inquires NSACF 133 whether it is permitted to continue the first slice in target RAN node 122 and whether it is permitted to register a second slice different from the first slice in target RAN node 122. SMF 132 inquires NSACF 133 whether it is permitted to continue the first slice in target RAN node 122 and whether it is permitted to establish a session for the second slice in target RAN node 122.
[0035] Then, NSACF 133 manages the number of UE registrations and sessions for each slice, and when the number of UE registrations for the first slice reaches a predetermined upper limit and the number of UE registrations for the second slice does not reach a predetermined upper limit, it responds to AMF 131 that it can register to the second slice.
[0036] In addition, when the number of sessions in the first slice reaches a predetermined upper limit and the number of sessions in the second slice does not reach the predetermined upper limit, the NSACF 133 responds to the SMF 132 that a session can be established in the second slice.
[0037] Upon receiving a response from NSACF 133 indicating that registration to slice 2 is possible, AMF 131 causes UE 110 to register to slice 2. Upon receiving a response from NSACF 133 indicating that a session can be established in slice 2, SMF 132 causes UE 110 to establish a session for slice 2 in target RAN node 122.
[0038] Figure 2 This is a sequence diagram showing the operation in the mobile communication system 100 according to the first embodiment.
[0039] Assume that the first slice and the second slice serving as its replacement slice are pre-configured as a slice mapping list in the source RAN node 121, the target RAN node 122, the AMF 131, and the SMF 132. Furthermore, assume that upon initial connection to the network, the UE 110 performs access registration in the first slice, a PDU session in the first slice, i.e., a first PDU session, is established, and PDU session switching is configured to be performed in, for example, SSC mode 3 (Session and Service Continuity mode 3).
[0040] When the UE 110 recognizes that handover is required in inter-RA mobility in the source RAN node 121 being accessed, the source RAN node 121 sends a handover request in the first PDU session to the target RAN node 122 of the mobility destination ( S10 ).
[0041] Here, UE 110 performs a handover from source RAN node 121 to target RAN node 122. Specifically, target RAN node 122 sends a handover command to source RAN node 121 (S11). Source RAN node 121 receives the handover command and sends it to UE 110 (S12). Upon receiving the handover command, UE 110 switches the transmission destination from RAN node 121 to target RAN node 122 and notifies target RAN node 122 of the handover completion (S13). At this point, the PDU session in the first slice, i.e., the first PDU session, is maintained.
[0042] Furthermore, when UE 110 recognizes that a handover is required during inter-RA mobility at the source RAN node 121 being accessed, in addition to the actions in step S10, the UE 110 also notifies the AMF 131 of the occurrence of the handover (S14). Upon receiving this notification, AMF 131 conveys this information to SMF 132 (S15). Steps S14 and S15 may also be performed before step S10.
[0043] The AMF 131 and the SMF 132 inquire of the NSACF 133 whether the first slice can be continued and whether the second slice can be provided (S16).
[0044] Specifically, AMF 131 inquires whether UE 110 can be registered to the first slice in the target RAN node as the switching destination and whether UE 110 can be registered to the second slice, and SMF 132 inquires whether a PDU session to the first slice in the target RAN node as the switching destination, that is, the first PDU session, can be established, and whether a PDU session to the second slice, that is, the second PDU session, can be established.
[0045] In response to this, the NSACF 133 returns whether the first slice can be continued and whether the second slice can be provided (S17).
[0046] Specifically, the upper limit of the number of UEs that can register with a slice and the upper limit of the number of PDU sessions that can be established for a slice are set in NSACF 133. Furthermore, NSACF 133 constantly monitors the number of UEs registered with a slice and the number of PDU sessions established for a slice. In response to inquiries from AMF 131 in step S16 regarding registration with the first slice and registration with the second slice, and inquiries from SMF 132 regarding establishment of the first PDU session and establishment of the second PDU session, NSACF 133 responds to AMF 131 and SMF 132 based on whether the monitored number exceeds the upper limit.
[0047] Here, the AMF 131 and SMF 132 determine, based on the response from the NSACF 133, that the first slice in the target RAN node 122 cannot be continued, but the second slice can be provided. In other words, it is assumed that the AMF 131 receives a response from the NSACF 133 indicating that registration with the first slice is not possible but registration with the second slice is possible, and the SMF 132 receives a response indicating that a session for the first slice cannot be established but a session for the second slice can be established.
[0048] In this case, the AMF 131 requests the UE 110 to set the 1st slice and the 2nd slice as allowed NSSAI by sending a UE configuration update (S18).
[0049] Upon receiving such a request, UE 110 notifies AMF 131 of the completion of the configuration of the first and second slices (S19).
[0050] In addition, the AMF 131 sends an update request to the SMF 132 to change the PDU session by replacing the first slice with the second slice (S20).
[0051] The SMF 132 that has received such an update request notifies the UE 110 of the change from the first slice to the second slice using a NAS (Non-Access Stratum) PDU session change command ( S21 ).
[0052] As a result, UE 110 establishes a PDU session in the second slice, that is, a second PDU session ( S22 ).
[0053] When the SSC mode 3 timer expires ( S23 ), the SMF 132 disconnects the PDU session in the first slice ( S24 ).
[0054] As a result, AMF 131 changes the setting of UE 110 to set the allowed slice to only the second slice in the UE configuration update (S25).
[0055] Through the above actions, the switching of the PDU session from the first session to the second session is performed uninterruptedly, and the slice control of the UE 110 can be continued uninterruptedly.
[0056] In addition, the above assumes that PDU session switching is performed in SSC mode 3, but it can also be performed through other PDU session switching methods.
[0057] Implementation Method 2
[0058] Figure 3 This is a block diagram schematically showing the configuration of a mobile communication system 200 according to the second embodiment.
[0059] In addition, Figure 3 , only elements related to this embodiment are shown, and description of other elements is omitted.
[0060] The mobile communication system 200 has a UE 110 , a RAN 220 , and a core network 230 .
[0061] UE 110 of mobile communication system 200 according to the second embodiment is the same as UE 110 of mobile communication system 100 according to the first embodiment.
[0062] RAN 220 is a wireless base station network.
[0063] RAN 220 includes at least RAN node 221 to which UE 110 was connected before handover and target RAN node 222, which is the handover destination of UE 110. RAN node 221 is also referred to herein as a connection source base station or a first base station, and target RAN node 222 is also referred to herein as a connection destination base station or a second base station.
[0064] The core network 230 is a 5G core network.
[0065] Part of the functionality of the core network 230 includes AMF 231A, target AMF 231B, SMF 132 and NSACF 133.
[0066] The SMF 132 and NSACF 133 of the core network 230 in the second embodiment are the same as the SMF 132 and NSACF 133 of the core network 130 in the first embodiment.
[0067] AMF 231A and target AMF 231B are both management functions for network access.
[0068] In embodiment 2, the source RAN node 221 is connected to the source AMF 231A, and the target RAN node 122 is connected to the target AMF 231B.
[0069] Then, the source AMF 231A functions as the first access management unit that notifies the target AMF 231B connected to the switching destination of the UE 110 connected to the source RAN node 221.
[0070] In addition, the target AMF 231B functions as a second access management unit that collaborates with the NSACF regarding the registration of the slice category of the UE 110 accessing the target RAN node 122.
[0071] In the second embodiment, when UE 110, which has established a session in the first slice, needs to be handed over to the target RAN node 222, the source RAN node 221 notifies the source AMF 231A of the handover of UE 110. The source AMF 231A notifies the target AMF 231B of the handover of UE 110. The target AMF 231B notifies the SMF 132 of the handover of UE 110 and inquires the NSACF 133 whether it is permitted to continue the first slice in the target RAN node 222 and whether it is permitted to register a second slice different from the first slice in the target RAN node 222. The SMF 132 inquires the NSACF 133 whether it is permitted to continue the first slice in the target RAN node 222 and whether it is permitted to establish a session for the second slice in the target RAN node 222.
[0072] Then, NSACF 133 manages the number of UE registrations for each slice and the number of sessions for each slice. When the number of UE registrations for the first slice reaches a predetermined upper limit and the number of UE registrations for the second slice does not reach a predetermined upper limit, the target AMF 231B responds that registration to the second slice is possible.
[0073] In addition, when the number of sessions in the first slice reaches a predetermined upper limit and the number of sessions in the second slice does not reach the predetermined upper limit, the NSACF 133 responds to the SMF 132 that a session can be established in the second slice.
[0074] Upon receiving a response from NSACF 133 indicating that registration to slice 2 is possible, target AMF 231B causes UE 110 to register with slice 2. Furthermore, upon receiving a response from NSACF 133 indicating that a session can be established in slice 2, SMF 132 causes UE 110 to establish a session in slice 2 of target RAN node 122.
[0075] Figure 4 This is a sequence diagram showing the operations in the mobile communication system 200 according to the second embodiment.
[0076] Assume that the first slice and the second slice serving as its replacement slice are pre-configured as a slice mapping list in the source RAN node 221, the target RAN node 222, the source AMF 231A, the target AMF 231B, and the SMF 132. Furthermore, assume that upon initial connection to the network, the UE 110 performs access registration in the first slice, a PDU session in the first slice, i.e., a first PDU session, is established, and PDU session switching is configured to be performed in, for example, SSC mode 3 (Session and Service Continuity mode 3).
[0077] When the UE 110 recognizes that handover is required in the inter-RA movement in the source RAN node 221 being accessed, the source RAN node 221 sends a handover request in the first PDU session to the target RAN node 222 of the movement destination ( S30 ).
[0078] Here, UE 110 performs a handover from source RAN node 221 to target RAN node 222. Specifically, target RAN node 222 sends a handover command to source RAN node 221 (S31). Source RAN node 221 receives the handover command and sends it to UE 110 (S32). Upon receiving the handover command, UE 110 switches the transmission destination from RAN node 221 to target RAN node 222 and notifies target RAN node 222 of the handover completion (S33). At this point, the PDU session in the first slice, i.e., the first PDU session, is maintained.
[0079] In addition, when the UE 110 recognizes that a handover is required in the inter-RA mobility in the source RAN node 221 being accessed, in addition to the actions in step S30, the handover is also conveyed to the AMF 231A (S34).
[0080] The source AMF 231A, which receives such a message, notifies the UE 110 of the occurrence of the handover by sending a message requesting the establishment of the association information of the UE 110 to the target AMF 231B (S35).
[0081] The target AMF 231B receives the notification and formulates the association information of UE 110. Then, the target AMF 231B and SMF 132 ask NSACF 133 whether it can continue the first slice and whether it can provide the second slice (S36).
[0082] Specifically, the target AMF 231B inquires whether the UE 110 can be registered to the 1st slice in the target RAN node as the switching destination and whether the UE 110 can be registered to the 2nd slice, and the SMF 132 inquires whether a PDU session to the 1st slice in the target RAN node as the switching destination, that is, the 1st PDU session, and whether a PDU session to the 2nd slice, that is, the 2nd PDU session, can be established.
[0083] In response to this, the NSACF 133 replies whether the first slice can be continued and whether the second slice can be provided (S37).
[0084] Specifically, the upper limit of the number of UEs that can register with a slice and the upper limit of the number of PDU sessions that can be established for a slice are set in the NSACF 133. Furthermore, the NSACF 133 constantly monitors the number of UEs registered with a slice and the number of PDU sessions established for a slice. In response to inquiries from the target AMF 231B in step S36 regarding registration with the first slice and registration with the second slice, and inquiries from the SMF 132 regarding establishment of the first PDU session and establishment of the second PDU session, the NSACF 133 responds to the AMF 131 and SMF 132 based on whether the monitored number exceeds the upper limit.
[0085] Here, it is assumed that the target AMF 231B and SMF 132 determine that the first slice cannot be continued and that the second slice can be provided based on the response from the NSACF 133. In other words, it is assumed that the target AMF 231B receives a response from the NSACF 133 indicating that it cannot register with the first slice but can register with the second slice, and the SMF 132 receives a response indicating that it cannot establish a session for the first slice but can establish a session for the second slice.
[0086] Then, the target AMF 231B requests the UE 110 to set the 1st slice and the 2nd slice as allowed NSSAI by sending a UE configuration update (S38).
[0087] Upon receiving such a request, UE 110 notifies the target AMF 231B of the completion of the configuration when the configuration of the first slice and the second slice is completed (S39).
[0088] In addition, the target AMF 231B sends an update request to the SMF 132 to change the PDU session by replacing the first slice with the second slice (S40).
[0089] Upon receiving such an update request, the SMF 132 notifies the UE 110 of the change from the first slice to the second slice using a NAS PDU session change command ( S41 ).
[0090] As a result, UE 110 establishes a PDU session in the second slice, that is, a second PDU session ( S42 ).
[0091] When the SSC mode 3 timer expires ( S43 ), the SMF 132 disconnects the PDU session in the first slice ( S44 ).
[0092] As a result, the target AMF 231B makes a setting change (S45) of UE 110 in the UE configuration update to set the allowed slice to only the second slice.
[0093] Through the above actions, the switching of the PDU session from the first session to the second session is performed uninterruptedly, and the slice control of the UE 110 can be continued uninterruptedly.
[0094] In the above, it is assumed that PDU session switching is performed in SSC mode 3, but it can also be performed using other PDU session switching methods.
[0095] The AMF 131, SMF 132, NSACF 133, source AMF 231A, and target AMF 231B described above can be implemented by a computer.
[0096] In addition, when AMF 131, SMF 132, NSACF 133, source AMF 231A, and target AMF 231B are respectively composed of a computer, AMF 131 is also called an access management device, SMF 132 is also called a session management device, NSACF 133 is also called a slice control device, the source AMF 231A is also called the first access management device, and the target AMF 231B is also called the second access management device.
[0097] Description of labels
[0098] 100, 200: mobile communication system; 110: UE; 120, 220: RAN; 121, 221: RAN node; 122, 222: target RAN node; 130, 230: core network; 131: AMF; 231A: source AMF; 231B: target AMF; 132: SMF; 133: NSACF.
Claims
1. A mobile communication system, comprising: Base station 1; Base station 2; an access management unit that manages registration of a mobile terminal that establishes a session with the first base station and the second base station to a slice; a session management unit, which manages the session of the mobile terminal in the slice; as well as The slice control management department manages whether slices can be controlled. It is characterized by: When the mobile terminal that has established a session in the first slice needs to be handed over to the second base station, the first base station notifies the access management unit of the handover of the mobile terminal. The access management unit notifies the session management unit of the occurrence of the handover of the mobile terminal, and inquires the slice control management unit whether it can continue the first slice in the second base station and whether it can register to the second slice different from the first slice in the second base station, The session management unit inquires the slice control management unit whether the session of the first slice in the second base station can be continued and whether the session of the second slice in the second base station can be established.
2. The mobile communication system according to claim 1, wherein: The slice control management unit manages the number of registrations of the mobile terminals in each slice and the number of sessions in each slice. When the number of registrations of the mobile terminals in the first slice reaches a predetermined upper limit and the number of registrations of the mobile terminals in the second slice does not reach a predetermined upper limit, the access management unit is responded to that registration to the second slice is possible. When the number of sessions in the first slice reaches a predetermined upper limit and the number of sessions in the second slice does not reach a predetermined upper limit, the session management unit is responded to that a session can be established in the second slice.
3. The mobile communication system according to claim 2, wherein: The access management unit causes the mobile terminal to register with the second slice when receiving a response from the slice control management unit indicating that registration with the second slice is possible. Upon receiving a response from the slice control management unit indicating that a session can be established in the second slice, the session management unit causes the mobile terminal to establish a session in the second slice in the second base station.
4. A mobile communication system, comprising: Base station 1; Base station 2; a first access management unit configured to manage registration of a mobile terminal that establishes a session with the first base station into a slice; a second access management unit configured to manage registration of the mobile terminal establishing a session with the second base station into the slice; a session management unit, which manages the session of the mobile terminal in the slice; as well as The slice control management department manages whether slices can be controlled. It is characterized by: When the mobile terminal having established a session in the first slice needs to be handed over to the second base station, the first base station notifies the first access management unit of the handover of the mobile terminal. The first access management unit notifies the second access management unit of the occurrence of the handover of the mobile terminal, The second access management unit notifies the session management unit of the occurrence of the handover of the mobile terminal, and inquires the slice control management unit whether it can continue the first slice in the second base station and whether it can register to the second slice different from the first slice in the second base station. The session management unit inquires the slice control management unit whether the session of the first slice in the second base station can be continued and whether the session of the second slice in the second base station can be established.
5. The mobile communication system according to claim 4, wherein: The slice control management unit manages the registration number of the mobile terminals in each slice and the session number of each slice. When the registration number of the mobile terminals in the first slice reaches a predetermined upper limit and the registration number of the mobile terminals in the second slice does not reach the predetermined upper limit, the second access management unit is responded to be able to register to the second slice. When the session number of the first slice reaches a predetermined upper limit and the session number of the second slice does not reach the predetermined upper limit, the session management unit is responded to be able to establish a session in the second slice.
6. The mobile communication system according to claim 5, wherein: The second access management unit causes the mobile terminal to register with the second slice when receiving a response from the slice control management unit indicating that registration with the second slice is possible. Upon receiving a response from the slice control management unit indicating that a session can be established in the second slice, the session management unit causes the mobile terminal to establish a session in the second slice in the second base station.