Base station device for mobile communication network and network node

Abstract

A base station device for a mobile communication network according to the present invention comprises: a configuration means that configurates a connection, via a base station device, between a wireless device and a first network node connecting to a data network outside the mobile communication network; and a processing means that performs a change process of changing a first section in the connection to a second section in response to receiving, from a second network, a notification about changing the first section to the second section, wherein the first section is between the base station device and the first network node, and the second section is between the base station device and a third network node connecting to the data network.

Description

Base station device and network node of mobile communication network

[0001] The present disclosure relates to a base station device and a network node of a mobile communication network.

[0002] In a fifth-generation (5G) mobile communication network defined by the Third Generation Partnership Project (3GPP (registered trademark)), a wireless device (WD) communicates with a server device on a data network (DN) such as the Internet via a base station device (gNB) and one or more user plane functions (UPFs). A UPF is one of the network functions (NFs) implemented in a network node in the core network of a mobile communication network. A UPF connected to a DN is called an anchor UPF, and a UPF between a gNB and the anchor UPF is called an intermediate UPF.

[0003] To transmit user packets between the WD and the anchor UPF, the mobile communication network establishes a PDU session between the WD and the anchor UPF. The PDU session is a "connection" connecting the WD and the anchor UPF, and includes the radio section between the gNB and the WD and the N3 section between the gNB and the anchor UPF. N3 is the name of the interface between the gNB and the anchor UPF. The N3 section is configured as a so-called General Packet Radio System (GPRS) Tunneling Protocol (GTP) tunnel, and user packets are encapsulated in GTP packets and transported. In the following description, the WD that has established a PDU session with the anchor UPF is also referred to as the "WD accommodated by the anchor UPF (or the WD accommodated in the anchor UPF)."

[0004] Non-Patent Document 1 discloses two configurations for changing the anchor UPF of a PDU session. Note that in Non-Patent Document 1, one of the two configurations for changing the anchor UPF of a PDU session is called Session and Service Continuity (SSC) Mode 2, and the other is called SSC Mode 3. According to Non-Patent Document 1, in both SSC Mode 2 and SSC Mode 3, a new PDU session is established between the WD and the changed anchor UPF, and the original PDU session between the WD and the previous anchor UPF is deleted.

[0005] 3GPP (registered trademark) TS 23.502 V18.4.0, December 2013

[0006] Using network function virtualization (NFV), UPFs can be implemented on general-purpose computers. NFV also makes it possible to control the number of UPFs (UPF instances) implemented on a computer depending on the load of the UPFs. For example, if the load on a first anchor UPF becomes too high, a second anchor UPF can be launched and some of the WDs accommodated in the first anchor UPF can be migrated (relocated) to the second anchor UPF. Furthermore, if the load on the second anchor UPF becomes too low, all WDs accommodated in the second anchor UPF can be migrated to another anchor UPF, and the second anchor UPF can then be deleted.

[0007] In such a case, by changing only the N3 section between the gNB and the anchor UPF while leaving the radio section between the WD and the gNB of the PDU session unchanged, the anchor UPF can be changed without changing the address used by the WD in communication, for example, the Internet Protocol (IP) address. However, in Non-Patent Document 1, when changing the anchor UPF, a new PDU session is created, and a procedure for changing only the N3 section is not defined.

[0008] According to one aspect of the present disclosure, a base station device of a mobile communication network includes a setting means configured to set up a connection via the base station device between a wireless device and a first network node connected to a data network external to the mobile communication network, and a processing means configured to perform a change process to change a first section of the connection between the base station device and the first network node to a second section between the base station device and a third network node connected to the data network in response to receiving a notification from a second network node to change the first section to the second section.

[0009] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals.

[0010] FIG. 1 is a diagram illustrating the configuration of a mobile communication system used to explain an embodiment. FIG. 2 is an explanatory diagram illustrating a process of changing a UPF that accommodates a WD. FIG. 3 is a diagram illustrating an example sequence of an N3 section change process accompanying the addition of a UPF. FIG. 4 is a diagram illustrating an example sequence of an N3 section change process accompanying the deletion of a UPF. FIG. 5 is a diagram illustrating an example sequence of an N3 section change process accompanying the addition of a UPF. FIG. 6 is a diagram illustrating an example configuration of an N3 section change process accompanying the deletion of a UPF. FIG. 7 is a diagram illustrating an example configuration of a base station device. FIG. 8 is a diagram illustrating an example configuration of a network node that implements an SMF. FIG. 9 is a diagram illustrating an example configuration of a network node that implements a controller.

[0011] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be arbitrarily combined. Furthermore, the same reference numerals are used for the same or similar components, and redundant explanations will be omitted.

[0012] Note that the following embodiments will be described using terminology used in 5G mobile communication networks defined by 3GPP (registered trademark). However, the following disclosure may also be applied to mobile communication networks of generations other than 5G. For example, an anchor UPF in 5G corresponds to a packet data network gateway (PGW) in fourth generation (4G). Furthermore, a PDU session in 5G, i.e., a connection connecting a WD and an anchor UPF, corresponds to a 4G bearer.

[0013] 1 is a configuration diagram of a mobile communication system used to explain an embodiment. The mobile communication system includes a mobile communication network, one or more WDs 1 connected to a gNB 2 of the mobile communication network, and a DN 9 connected to a core network 3 of the mobile communication network. The mobile communication network includes the core network 3 and multiple gNBs 2 connected to the core network 3. The DN 9 is, for example, the Internet.

[0014] The core network 3 includes various network functions (NFs). The access and mobility management function (AMF) 4, session management function (SMF) 5, UPF 6, and controller 7 shown in Figure 1 are some of the NFs included in the core network 3. The NFs can be realized as instances on a general-purpose computer based on NFV. The AMF 4 has a function to manage the mobility of the WD 1. The SMF 5 has a function to manage PDU sessions, such as setting up and deleting PDU sessions for the WD 1.

[0015] UPF6 has the function of forwarding user packets received from WD1 to DN9 via a PDU session established with WD1, and forwarding user packets addressed to WD1 received from DN9 to WD1 via the PDU session with WD1. As described above, of the PDU sessions established between WD1 and UPF6, the section between gNB2 and UPF6 is referred to as the N3 section.

[0016] The rules (processing rules) for the UPF 6 to process user packets are set in the UPF 6 by the SMF 5. The processing rules include packet detection rules (PDRs) that indicate user packets to be detected, forwarding action rules (FARs) that indicate how to forward user packets detected by the PDRs, etc. The UPF 6 forwards packets detected based on the PDRs in accordance with the FARs associated with the PDRs.

[0017] In the N3 section of the PDU session, user packets are transmitted via a GTP tunnel. A tunnel endpoint identifier (TEID) is set at each end of the GTP tunnel. In the following description, the TEID on the gNB2 side is referred to as TEID#1, and the TEID on the UPF6 side is referred to as TEID#2. TEID#1 is also the identifier of the GTP tunnel in the direction from UPF6 to gNB2, and TEID#2 is also the identifier of the GTP tunnel in the direction from gNB2 to UPF6. In other words, TEID#1 is set as the destination in the header of a GTP packet sent by UPF6, and TEID#2 is set as the destination in the header of a GTP packet sent by gNB2. UPF6 can determine which PDU session a packet belongs to based on the TEID#2 set in the header of the received GTP packet. Similarly. gNB2 can determine which PDU session the packet belongs to based on the TEID #1 set in the header of the received GTP packet.

[0018] The controller 7 has a function of adding / removing a UPF 6 based on the NFV and a function of controlling routing in the gateway (GW) 8. When the processing load of a UPF 6 becomes too high, the controller 7 triggers a UPF addition process in which a new UPF 6 is started up and a part of the WDs 1 accommodated in the UPF 6 with the excessively high processing load is moved to the newly started UPF 6. Figure 2 is an explanatory diagram of the UPF addition process.

[0019] In the upper part of Figure 2, two WDs 1 (referred to as WD #1 and WD #2) have established a PDU session with a UPF 6 (referred to as UPF #1) via a gNB 2. Note that UPF #1 has also established PDU sessions with many WDs 1 other than WD #1 and WD #2, and the processing load of UPF #1 is assumed to be too high. In this case, the controller 7 adds a new UPF #2 and moves some of the WDs 1 accommodated by UPF #1 to UPF #2, thereby reducing the processing load of UPF #1. As shown in the lower part of Figure 2, WD #1 is still accommodated in UPF #1, but WD #2 has been re-accommodated to UPF #2. In this case, in this embodiment, the accommodation of WD #1 is performed by switching (changing) only the N3 section between the gNB 2 and the UPF 6. The dashed line between gNB2 and UPF#1 at the bottom of Figure 2 indicates the N3 section of the PDU session of WD#2 before the re-accommodation, and the solid line between gNB2 and UPF#2 indicates the N3 section of the PDU session of WD#2 after the re-accommodation.

[0020] Note that, since WD#2 has been relocated from UPF#1 to UPF#2, user packets addressed to WD#2 received from DN9 must be routed so that they are received by UPF#2. Although not shown in FIG. 2 , GW8 has a function of routing packets destined for WD1 to the appropriate UPF 6. In this embodiment, routing in GW8 is controlled by the controller 7. However, a configuration in which the controller 7 notifies other devices of necessary routing information, and the other devices control routing in GW8, may also be adopted. For example, if multiple UPF instances are implemented in one computer, GW8 is a function implemented within the single computer. Furthermore, if one UPF instance is implemented in each of multiple computers, GW8 is implemented in another computer connected to each of the multiple computers. Furthermore, if multiple UPF instances are implemented in each of multiple computers, GW8 is implemented in a distributed manner in each of the multiple computers and in another computer connected to each of the multiple computers.

[0021] When a UPF 6 experiences a processing load that is too low, the controller 7 triggers a UPF deletion process in which all UPFs 6 accommodated in the UPF 6 are moved to other UPFs 6 and the UPF 6 is deleted. For example, in the lower part of FIG. 2, assume that the processing load of UPF #2 is too low. In this case, the controller 7 re-accommodates all WDs 1 accommodated in UPF #2 to other UPFs 6 and deletes UPF #2. For example, if WD #2 is re-accommodated in UPF #1, the configuration after the re-accommodation will be as shown in the upper part of FIG. 2. In this case, the re-accommodation of WD #1 is performed by simply changing the N3 section. Furthermore, the controller 7 controls the GW 8 so that user packets addressed to WD #2 received from the DN 9 are routed to UPF #1.

[0022] The controller 7 triggers a UPF addition process when the processing load of the UPF 6 satisfies a first trigger condition, and triggers a UPF deletion process when the processing load of the UPF 6 satisfies a second trigger condition. Note that both the UPF addition process and the UPF deletion process involve a process of changing the N3 section to re-accommodate the WD1 accommodated in the added UPF 6 or the WD1 accommodated in the UPF 6 to be deleted.

[0023] In this embodiment, the processing load of the UPF 6 is evaluated by the amount of traffic processed by the UPF 6. For this reason, the controller 7 periodically acquires from the UPF 6 the traffic amount of each PDU session set by the UPF 6. The traffic amount of one PDU session may be, for example, the downlink direction, that is, the amount of traffic transmitted toward WD1. The traffic amount of one PDU session may be, for example, the uplink direction, that is, the amount of traffic received from WD1. Furthermore, the traffic amount of one PDU session may be the sum of the traffic amounts in the downlink and uplink directions. Furthermore, the traffic amount of one PDU session may be the weighted sum of the traffic amounts in the downlink and uplink directions.

[0024] The controller 7 calculates the total traffic volume of the PDU sessions set by each UPF 6 for each UPF 6. When a UPF 6 whose total value exceeds a first threshold is found, the controller 7 determines that the first trigger condition is satisfied and triggers a UPF addition process. When a UPF 6 whose total value falls below a second threshold is found, the controller 7 determines that the second trigger condition is satisfied and triggers a UPF deletion process. Here, the second threshold is smaller than the first threshold. In this embodiment, the first and second trigger conditions are based on the traffic volume processed by the UPF 6. However, they may also be based on a parameter correlated with the processing load of the UPF 6, such as a processor utilization rate for processing by the UPF 6. In this case, the first trigger condition is satisfied when the processor utilization rate exceeds the first threshold, and the second trigger condition is satisfied when the processor utilization rate falls below the second threshold.

[0025] 3 shows a sequence of processing for changing the N3 section in response to the addition of a UPF 6 in this embodiment. In S1, the controller 7 detects that the total traffic volume of UPF #1 satisfies a first trigger condition. In response to the trigger detection, the controller 7 triggers a UPF addition process. Triggering the UPF addition process also triggers a process for changing the N3 section. In S2, the controller 7 executes a process for starting up a new UPF #2. The UPF #2 startup process includes a process for starting an instance of UPF #2 on a computer and a process required to make UPF #2 available. The process required to make UPF #2 available may include a process for assigning an identifier for identifying UPF #2 to UPF #2 and a process for establishing an association between the SMF 5 and UPF #2. The identifier of UPF #2 may be address information indicating UPF #2 in communication with UPF #2, such as the IP address of UPF #2.

[0026] In S3, the controller 7 determines which WD1, among the WD1s accommodated in UPF #1, should be re-accommodated in UPF #2. That is, the controller 7 determines which PDU sessions, among the PDU sessions set by UPF #1, should be migrated to UPF #2. The controller 7 migrates some of the PDU sessions set by UPF #1 to UPF #2, thereby determining which PDU sessions to migrate to UPF #2 so that the total value of the traffic volume of UPF #1 no longer satisfies the first trigger condition. In this embodiment, the controller 7 determines which PDU sessions to migrate to UPF #2 so that the total value of the traffic volume of UPF #1 after the migration is approximately half of that before the migration. As an example, the controller 7 sorts each PDU session set by UPF #1 in descending order of the traffic volume of each PDU session, and determines to leave one of the odd-numbered and even-numbered sessions in UPF #1 and migrate the other to UPF #2. In the following description, the PDU session to be transitioned to UPF #2 is referred to as the target PDU session. Also, the WD1 using the target PDU session is also referred to as the target WD1.

[0027] In S4, the controller 7 notifies the SMF 5 of the relocation of the PDU session. This notification also notifies the change of the N3 section of the target PDU session. This notification includes information indicating the target PDU session, for example, the identifier of the target PDU session and the identifier of the UPF #2 to which it is relocated.

[0028] The processing from S5 onwards is performed for each target PDU session. In other words, the processing from S5 onwards shows a sequence for one target PDU session. In S5, the SMF5 notifies the gNB2 terminating the N3 section of the target PDU session of the change in the N3 section. The notification includes the identifier of the target PDU session and the identifier of the UPF#2 to which it is relocated. The identifier of the UPF#2 may be address information of the UPF#2, such as the IP address of the UPF#2 for communicating with the UPF#2. In S6, in response to the notification in S5, the gNB2 notifies the SMF5 of the TEID#1 to be used on the receiving side of the gNB2 after the change in the N3 section.

[0029] When SMF5 receives TEID#1 from gNB2, it determines TEID#2 to be used on the receiving side of UPF#2 after the N3 section is changed, and generates a processing rule for the target PDU session based on TEID#1 received from gNB2 and the TEID#2 determined by SMF5. Then, in S7, SMF5 instructs UPF#2 to set the N3 section. The instruction includes the processing rule generated for the target PDU session. Note that the processing rule is basically the same as the one used by UPF#1 for the target PDU session, but the values ​​of TEID#1 and TEID#2 are changed according to the change in the N3 section.

[0030] Furthermore, in S8, SMF5 instructs gNB2 to change the N3 section. This instruction may include the identifier of the target PDU session and information indicating the TEID#2 to be used on the receiving side of UPF#2 after the N3 section is changed. Subsequently, in S9, SMF5 instructs UPF#1 to delete the N3 section of the target PDU session. Furthermore, in S10, SMF5 notifies the controller 7 of the completion of the re-accommodation. This notification includes the identifier of the target PDU session for which re-accommodation has been completed. In S11, the controller 7 controls GW8 so that user packets carried on the target PDU session for which re-accommodation has been completed are routed to UPF#2. As a result, gNB2 transmits user packets received from WD1 using the target PDU session to UPF#2. Furthermore, UPF#2 transmits user packets addressed to WD1 using the target PDU session on the target PDU session.

[0031] 4 shows a sequence of processing for changing the N3 section accompanying the deletion of a UPF 6 in this embodiment. In S20, the controller 7 detects that the total traffic volume of UPF #2 satisfies the second trigger condition. In response to the trigger detection, the controller 7 triggers the UPF deletion processing. Triggering the UPF deletion processing also triggers processing for changing the N3 section. In the case of the UPF deletion processing, all PDU sessions set in UPF #2 that satisfy the second trigger condition become target PDU sessions. In S21, the controller 7 determines the UPF 6 to which the target PDU session is to be relocated (changed to). Note that the controller 7 determines the UPF 6 to which the target PDU session is to be relocated so that the relocation of the target PDU session does not cause the UPF 6 to satisfy the first trigger condition. If the relocation of the target PDU session causes any UPF 6 to satisfy the first trigger condition, the controller 7 puts the processing for changing the N3 section on hold.

[0032] If the target PDU session can be relocated so that no UPF 6 that satisfies the first trigger condition occurs, the controller 7 notifies the SMF 5 of the reaccommodation of the PDU session in S22. This notification also notifies the change of the N3 section of the target PDU session. This notification includes information indicating the target PDU session, for example, the identifier of the target PDU session and the identifier of the UPF 6 to which it is to be relocated. In the following description, it is assumed that all PDU sessions established by UPF #2 are moved to UPF #1.

[0033] The processes from S23 to S28 are performed for each target PDU session. In other words, the processes from S23 to S28 show a sequence for one target PDU session. In S23, the SMF5 notifies the gNB2 terminating the N3 section of the target PDU session of the change in the N3 section. The notification includes the identifier of the target PDU session and the identifier of the UPF#1 to which it is relocated. The identifier of the UPF#1 may be address information of the UPF#1, such as the IP address of the UPF#1 for communicating with the UPF#1. In S24, in response to the notification in S23, the gNB2 notifies the SMF5 of the TEID#1 to be used on the receiving side of the gNB2 after the change in the N3 section.

[0034] When SMF5 receives TEID#1 from gNB2, it determines TEID#2 to be used on the receiving side of UPF#1 after the N3 section is changed, and generates a processing rule for the target PDU session based on TEID#1 received from gNB2 and TEID#2 determined by SMF5. Then, in S25, SMF5 instructs UPF#1 to set the N3 section. The instruction includes the processing rule generated for the target PDU session. The processing rule includes information indicating TEID#1 received from gNB2 and TEID#2 determined by SMF5. Note that the processing rule is basically the same as the one used by UPF#2 for the target PDU session, but the values ​​of TEID#1 and TEID#2 are changed in accordance with the change in the N3 section.

[0035] Furthermore, in S26, SMF5 instructs gNB2 to change the N3 section. This instruction may include the identifier of the target PDU session and information indicating the TEID#2 to be used on the receiving side of UPF#1 after the N3 section is changed. Furthermore, in S27, SMF5 notifies the controller 7 of the completion of the reaccommodation. This notification includes the identifier of the target PDU session for which reaccommodation has been completed. In S28, the controller 7 controls GW8 so that user packets carried on the target PDU session for which reaccommodation has been completed are routed to UPF#1. As a result, gNB2 transmits user packets received from WD1 using the target PDU session to UPF#1. In addition, UPF#1 transmits user packets addressed to WD1 using the target PDU session on the target PDU session. When the reaccommodation of all target PDU sessions is completed, the controller 7 performs processing to delete UPF#2 in S29.

[0036] As described above, according to this embodiment, the anchor UPF can be changed by changing only the N3 section. In particular, in this embodiment, the anchor UPF can be changed without changing the address of WD1, for example, the IP address, used by WD1 in communication with a server device on DN9. Note that it is not essential to not change the address of WD1, and the SMF may assign a new IP address or the like to WD1 in response to a change in the N3 section. In this case, the new address of WD1 can be notified to WD1 via gNB2, for example, in S8 of FIG. 3 or S26 of FIG. 4.

[0037] <Second embodiment> Next, the second embodiment will be described, focusing on the differences from the first embodiment. In the first embodiment, the SMF5 communicated directly with the gNB2 in S5, S6, and S8 of FIG. 3, and S23, S24, and S26 of FIG. 4. In this embodiment, the SMF5 and the gNB2 communicate via the AMF4, similar to the normal PDU session setup process. That is, the processes of S5, S6, and S8 of FIG. 3, and S23, S24, and S26 of FIG. 4 are executed via the AMF4. In this embodiment, there is no need to define a new interface between the SMF5 and the gNB2, and the N3 section can be changed simply by modifying the messages used in the already defined interface.

[0038] Third Embodiment Next, a third embodiment will be described, focusing on the differences from the first embodiment. Fig. 5 is a sequence diagram of the process of changing the N3 section with the addition of a UPF in this embodiment, and Fig. 6 is a sequence diagram of the process of changing the N3 section with the deletion of a UPF in this embodiment. Note that the same step numbers are used for the same processing steps as in Figs. 3 and 4, and detailed explanations thereof will be omitted.

[0039] In the case of adding a UPF, in S3, when the controller 7 determines WD1 to transition to UPF #2, the subsequent sequence is executed for each target PDU session. In other words, the processing from S30 onwards shows the sequence for one target PDU session. In S30, the controller 7 notifies the gNB2 terminating the N3 section of the target PDU session of the change in the N3 section. The notification includes the identifier of the target PDU session and the identifier of the UPF #2 to which it is relocated. In S31, in response to the notification in S30, the gNB2 notifies the controller 7 of the TEID #1 to be used on the receiving side of the gNB2 after the change in the N3 section.

[0040] When the controller 7 receives TEID #1 from the gNB 2, in S32, it notifies the SMF 5 of the reaccommodation of the PDU session. The notification includes the identifier of the target PDU session, the identifier of the UPF #2 to which it is relocated, and information indicating TEID #1 received from the gNB 2 in S31. The subsequent processing is the same as in the first embodiment.

[0041] In the case of deleting a UPF, the processes from S40 to S28 are a sequence for one target PDU session. In S40, the controller 7 notifies the gNB2 terminating the N3 section of the target PDU session of a change in the N3 section. The notification includes the identifier of the target PDU session and the identifier of the UPF #1 to which it is relocated. In S41, in response to the notification in S40, the gNB2 notifies the controller 7 of the TEID #1 to be used on the receiving side of the gNB2 after the change in the N3 section.

[0042] When the controller 7 receives TEID #1 from the gNB 2, in S42, it notifies the SMF 5 of the reaccommodation of the PDU session. The notification includes the identifier of the target PDU session, the identifier of the UPF #1 to which it is relocated, and information indicating TEID #1 received from the gNB 2 in S41. The subsequent processing is the same as in the first embodiment.

[0043] As described above, in this embodiment as well, the anchor UPF can be switched by changing only the N3 section.

[0044] <Device Configuration> FIG. 7 shows a configuration example of the base station device 20 exemplified as the gNB 2 in each of the above-described embodiments. The base station device 20 includes, for example, one or more processors and one or more memory devices. The one or more memory devices may include volatile memory devices and non-volatile memory devices. Each functional block shown in FIG. 7 may be realized by one or more processors executing a computer program stored in one or more memory devices. The base station device 20 may also be realized as a single device. Alternatively, the base station device 20 may be realized as multiple devices capable of communicating with each other. As an example, the base station device 20 may be composed of a radio unit (RU), a distributed unit (DU), and a central unit (CU), which may be located in different geographical locations. Furthermore, the CU may be separated into a CU-CP for the control plane and a CU-UP for the user plane. In addition, in a configuration in which the CU is separated into a CU-CP and a CU-UP, in the sequences of Figures 3 to 6, it is the CU-CP that communicates with the AMF 6, SMF 5, controller 7, etc. of the core network. Therefore, the gNB 2 in the sequences of Figures 3 to 6 can also be read as the CU-CP. Note that Figure 7 shows only the functional blocks necessary for understanding the present disclosure, and the base station device 20 may have functional blocks other than those shown in Figure 7.

[0045] The wireless communication unit 24 performs wireless communication processing with WD1. The communication unit 21 performs communication processing with the NF of the core network. The setting unit 22 sets a connection between WD1 and a first network node via the base station device 20. The first network node may be a node implementing UPF6. The connection may be, for example, a 5G PDU session. The connection includes a wireless section with WD1 and an N3 section with the first network node, and the first network node is connected to an external DN9. The processing unit 23 performs N3 section change processing in response to receiving a notification from the second network node indicating that the N3 section (first section) of the connection will be changed to another N3 section (second section) with a third network node connected to DN9. The third network node may be a node implementing another UPF6.

[0046] In the first embodiment, the second network node is a node that implements SMF5, in the second embodiment, the second network node is a node that implements AMF4, and in the third embodiment, the second network node is a node that implements controller 7.

[0047] In the change process, the processing unit 23 determines a first identifier (TEID#1) for the end of the changed N3 section, i.e., the second section, on the base station device 20 side, and notifies the second network node, and may receive a second identifier (TEID#2) for the end of the second section on the third network node side from a node implementing SMF5 or AMF4.

[0048] FIG. 8 shows a configuration example of a network node 50 that implements the above-described SMF5. The network node 50 includes, for example, one or more processors and one or more memory devices. The one or more memory devices may include volatile memory devices and non-volatile memory devices. Each functional block shown in FIG. 8 may be realized by one or more processors executing a computer program stored in the one or more memory devices. The network node 50 may also be realized by a single device. Alternatively, the network node 50 may be realized by multiple devices that can communicate with each other. Note that FIG. 8 shows only the functional blocks necessary for understanding the present disclosure, and the network node 50 may have functional blocks other than those shown in FIG. 8.

[0049] The communication unit 53 performs communication processing with the NF of the mobile communication network. The NF of the mobile communication network may include the AMF 4, the controller 7, and the gNB 2. The management unit 51 manages the connection between the WD 1 and a first network node connected to the DN 9 via the gNB 2. The first network node may be a node implementing the UPF 6. In response to receiving a notification from the second network node that the first section (N3 section) of the connection between the gNB 2 and the first network node is to be changed to the second section (N3 section) between the gNB 2 and a third network node connected to the DN 9, the processing unit 52 performs a change process to change the first section to the second section. The second network node may be a node implementing a function to monitor the load of the first network node, such as the controller 7 in each of the above embodiments. The third network node may be a node implementing another UPF 6.

[0050] In the change process, the processing unit 52 receives a first identifier (TEID#1) on the gNB2 side of the second section from the gNB2, AMF4 or second network node, determines a second identifier (TEID#2) on the third network node side of the second section, and notifies the third network node of the first identifier and the second identifier directly or via the AMF4.

[0051] FIG. 9 shows a configuration example of a network node 70 that implements the above-described controller 7. The network node 70 includes, for example, one or more processors and one or more memory devices. The one or more memory devices may include volatile memory devices and non-volatile memory devices. Each functional block shown in FIG. 9 may be realized by one or more processors executing a computer program stored in the one or more memory devices. The network node 70 may also be realized by a single device. Alternatively, the network node 70 may be realized by multiple devices that can communicate with each other. Note that FIG. 9 shows only the functional blocks necessary for understanding the present disclosure, and the network node 70 may have functional blocks other than those shown in FIG. 9.

[0052] The communication unit 75 performs communication processing with the NF of the mobile communication network. The monitoring unit 71 connects to the DN 9 and monitors the processing load of a first network node that accommodates one or more WDs 1. The first network node has a function of setting up a connection with each of the one or more WDs 1 via a gNB 2. The first network node may be a node that implements a UPF 6.

[0053] The decision unit 72 decides, based on the processing load of the first network node, to reaccommodate a target WD1 among one or more WDs 1 accommodated by the first network node to a second network node connected to the DN 9. The second network node may be a node implementing a UPF 6.

[0054] In response to the decision unit 72 deciding to re-accommodate the target WD1 to the second network node, the trigger unit 73 triggers a change process to change the first section (N3 section) between the first gNB2 and the first network node of the first connection established between the target WD1 and the first network node via the first gNB2 to the second section (N3 section) between the first gNB2 and the second network node.

[0055] The trigger unit 73 may notify the node implementing the SMF 5 of information indicating the first connection and the second network node. In the change process, the trigger unit 73 may receive the first identifier (TEID #1) on the first gNB 2 side of the second section from the first gNB 2 and notify the node implementing the SMF 5.

[0056] When the determiner 72 determines to re-accommodate the target WD1 to a second network node because the load on the first network node has become greater than a first threshold, the determiner 72 determines the target WD1 so that the load on the first network node is smaller than the first threshold, and when the determiner 72 determines to re-accommodate the target WD1 to a second network node because the load on the first network node has become smaller than a second threshold, the determiner 72 may determine all of the one or more WDs accommodating the first network node as the target WD1. Here, the second threshold is a value smaller than the first threshold. Note that the monitor 71 may monitor the total traffic volume of connections established between the first network node and one or more WDs 1 as the processing load of the first network node.

[0057] The control unit 74 controls the GW 8 so that user packets from the DN 9 are routed to the appropriate UPF 6 .

[0058] The present disclosure provides a computer program that, when executed by one or more processors in a device having one or more processors, causes the device to function as the above-described base station device 20, network node 50, or network 70, as well as a computer-readable storage medium storing the computer program. Furthermore, the present disclosure provides methods executed by the base station device 20, network node 50, or network 70 regarding the processes described in each embodiment, computer programs that cause a device having one or more processors to execute these methods, and computer-readable storage media storing the computer program.

[0059] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention.

[0060] This application claims priority based on Japanese Patent Application No. 2024-033176, filed March 5, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A base station device of a mobile communication network, comprising: setting means configured to set up a connection between a wireless device and a first network node connected to a data network external to the mobile communication network via the base station device; and processing means configured to, in response to receiving a notification from a second network node to change a first section of the connection between the base station device and the first network node to a second section between the base station device and a third network node connected to the data network, perform a change process to change the first section to the second section.

2. The base station device according to claim 1, wherein the second network node is a node that implements a session management function (SMF), a node that implements an access and mobility management function (AMF), or a node that implements a function for monitoring the load of the first network node.

3. The base station device according to claim 1 or 2, wherein the first network node and the third network node are nodes that implement a user plane function (UPF).

4. The base station device according to claim 3, wherein the processing means is configured to, in the change processing, determine a first identifier for the end of the second section on the base station device side and notify the second network node, and receive a second identifier for the end of the second section on the third network node side from a node implementing a session management function (SMF) or an access and mobility management function (AMF).

5. A network node of a mobile communication network, comprising: management means configured to manage a connection between a wireless device and a first network node connected to a data network external to the mobile communication network, via a base station; and processing means configured to, in response to receiving a notification from a second network node to change a first section of the connection between the base station and the first network node to a second section between the base station and a third network node connected to the data network, perform a change process to change the first section to the second section.

6. The network node according to claim 5, wherein the second network node is a node that implements a function for monitoring the load of the first network node.

7. A network node according to claim 5 or 6, wherein the first network node and the third network node are nodes implementing a user plane function (UPF).

8. A network node according to any one of claims 5 to 7, wherein the network node is a node implementing a session management function (SMF).

9. A network node according to any one of claims 5 to 8, wherein the processing means is configured to, in the change processing, receive a first identifier on the base station device side of the second section from the base station device, a node implementing an Access and Mobility Management Function (AMF), or the second network node, determine a second identifier on the third network node side of the second section, and notify the third network node of the first identifier and the second identifier.

10. A network node of a mobile communication network, comprising: a first network node connected to a data network external to the mobile communication network and accommodating one or more wireless devices, the first network node being configured to monitor a load of the first network node which establishes a connection via a base station device with each of the one or more wireless devices; a determination means configured to decide to re-accommodate a target wireless device among the one or more wireless devices accommodated by the first network node to a second network node connected to the data network based on the load of the first network node; and a trigger means configured to trigger a change process to change a first section between the first base station device and the first network node of a first connection established between the target wireless device and the first network node via the first base station device to a second section between the first base station device and the second network node in response to the determination means' decision to re-accommodate the target wireless device to the second network node.

11. The network node according to claim 10, wherein the first network node and the second network node are nodes implementing a user plane function (UPF).

12. A network node according to claim 10 or 11, wherein the trigger means is configured to notify a node implementing a session management function (SMF) of information indicating the first connection and the second network node during the change process.

13. A network node according to any one of claims 10 to 12, wherein the trigger means is configured to receive a first identifier on the first base station device side of the second section from the first base station device during the change processing and notify the SMF of the first identifier.

14. The network node according to any one of claims 10 to 13, wherein the determination means is configured to, when it is determined that the target wireless device should be re-accommodated to the second network node because the load on the first network node has become greater than a first threshold, determine the target wireless device so that the load on the first network node is smaller than the first threshold, and, when it is determined that the target wireless device should be re-accommodated to the second network node because the load on the first network node has become smaller than a second threshold, determine all of the one or more wireless devices accommodated by the first network node as the target wireless devices, wherein the second threshold is smaller than the first threshold.

15. A network node according to any one of claims 10 to 14, wherein the monitoring means is configured to monitor the total traffic volume of the connections established between the first network node and the one or more wireless devices as the load of the first network node.

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