Communication system and communication method

Abstract

This communication system includes a plurality of gateways that are connected to a mobile network and a plurality of edge servers, and a path selection controller that selects a communication path in the mobile network. The gateway has a notification unit that, if a path failure has been detected in a path to the edge server, notifies the path selection controller of information relating to a communication terminal that uses the path in which the path failure has been detected. The path selection controller has a session management unit that, on the basis of the information relating to the communication terminal, switches the communication path in the mobile network used by the communication terminal that uses the path to a communication path to a gateway different from the gateway in which the path failure has been detected among the plurality of gateways.

Description

Communication system and communication method

[0001] The present invention relates to a communication system and a communication method.

[0002] Standardization organizations such as 3GPP (registered trademark) are currently developing specifications for Multi-access Edge Computing (MEC). MEC enables communication that meets strict latency requirements, such as for autonomous driving, by performing service processing on edge servers located close to user terminals.

[0003] Also, a technique is known in which the connection delay to each edge server is calculated and a route is switched so that each user terminal is connected to the server with the smallest delay (see, for example, Patent Document 1).

[0004] 5G; Procedures for the 5G System (5GS) (3GPP TS 23.502 version 16.7.0 Release 16).<https: / / www.etsi.org / deliver / etsi_ts / 123500_123599 / 123502 / 16.07.00_60 / ts_123502v160700p.pdf> Baba et al., "Research on next-generation mobile network control methods considering communication routes via edge networks," FIT2021 (20th Forum on Information Science and Technology), M-024, No. 20, Part 4, pp. 223-228, August 12, 2021.<https: / / www.ieice.org / publications / conference-FIT-DVDs / FIT2021 / data / pdf / M-024.pdf>

[0005] International Publication No. 2022 / 013907

[0006] Generally, when connecting a UPF (User Plane Function) in a mobile network to an edge server, a gateway (hereinafter referred to as GW) is installed for each edge server. However, with this method, the required GW resources increase as the number of connected edge servers increases, so it is required that one GW can accommodate the connection destinations of multiple edge servers.

[0007] However, in the conventional technology, when a GW detects a route failure, the communication terminals accommodated in the GW are diverted to another GW. Therefore, if a GW has multiple connection destinations, even a single route failure will cause route switching for all of the connection destinations accommodated. As a result, if the nearest UPF is not selected, delays may increase and the service quality of the edge server may deteriorate.

[0008] The technology disclosed in Patent Document 1 makes it possible to switch routes even if a route failure occurs, but it is necessary to calculate the delay for each service (edge ​​server), and it is necessary to set information about the server and UPF name related to the communication terminal in advance.

[0009] As described above, in conventional technology, in a communication system in which a gateway accommodates connection destinations of multiple edge servers, when a route failure occurs, it is difficult to selectively detour communication terminals using the route on which the route failure has occurred to another gateway.

[0010] An embodiment of the present invention has been made in consideration of the above-mentioned problems, and in a communication system in which a GW accommodates connection destinations of multiple edge servers, when a route failure occurs, it makes it easy to selectively detour communication terminals using the route on which the route failure has occurred to another GW.

[0011] In order to solve the above problems, a communication system according to an embodiment of the present invention is a communication system including a mobile network and a plurality of gateways connected to a plurality of edge servers, and a route selection controller that selects a communication route within the mobile network, wherein the gateway has a notification unit that, when a route failure is detected on a route to the edge server, notifies the route selection controller of information about a communication terminal that uses the route that detected the route failure, and the route selection controller has a session management unit that, based on the information about the communication terminal, switches the communication route within the mobile network used by the communication terminal that uses the route to a communication route to a gateway among the plurality of gateways that is different from the gateway that detected the route failure.

[0012] According to one embodiment of the present invention, in a communication system in which a gateway accommodates connection destinations of multiple edge servers, when a route failure occurs, it becomes easy to selectively detour communication terminals using the route on which the route failure has occurred to another gateway.

[0013] FIG. 1 is a diagram illustrating an example of a system configuration of a communication system according to the present embodiment. FIG. 2 is a diagram illustrating an example of a functional configuration of a GW according to the present embodiment. FIG. 3 is a diagram illustrating an example of a functional configuration of a route selection controller according to the present embodiment. FIG. 4 is a sequence diagram illustrating an example of processing of a communication system according to the present embodiment. FIG. 5 is a diagram (1) for explaining processing of a communication system according to the present embodiment. FIG. 6 is a diagram (2) for explaining processing of a communication system according to the present embodiment. FIG. 7 is a diagram illustrating an example of a hardware configuration of a computer. FIG. 8 is a diagram (1) for explaining background and issues. FIG. 9 is a diagram (2) for explaining background and issues.

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0015] <Summary> (Background) Standardization organizations such as 3GPP (3rd Generation Partnership Project) are currently developing MEC (Multi-access Edge Computing) specifications. MEC enables communication that meets strict communication latency requirements for autonomous driving and other applications by performing service processing on edge servers installed near user terminals, rather than on servers in centralized data centers as in the past. In addition, because the same processing can be performed on servers at all edge locations available to the user, services can be provided at locations close to the user even if the user moves and changes the edge location they connect to.

[0016] (Issue) An APN (Access Point Name) is generally set in association with an edge server to which the APN is connected. For example, as shown in FIG. 9, a gateway (hereinafter referred to as GW) needs to be installed for each edge server.

[0017] In the example of FIG. 9, the communication system 1 includes UEs (User Equipment) 10a and 10b, a route selection controller 20, UPFs (User Plane Functions) 21a and 21b, GWs (Gateways) 30a-1, 30a-2, 30b-1, and 10b-2, and edge servers 40a and 40b.

[0018] In the following description, when referring to any UE among the UEs 10a and 10b, "UE 10" is used. When referring to any UPF among the UPFs 21a and 21b, "UPF 21" is used. When referring to any GW among the GWs 30a-1, 30a-2, 30b-1, and 10b-2, "GW 30" is used. When referring to any edge server among the edge servers 40a and 40b, "edge server 40" is used.

[0019] The UE 10 is an example of a communication terminal that communicates with the edge server 40 via the mobile network 2. The mobile network 2 is, for example, a mobile network such as 5G (5th Generation) or LTE (Long Term Evolution). Here, the following description will be given assuming that the mobile network 2 is a 5G mobile network, but the mobile network 2 may be a mobile network other than 5G.

[0020] The path selection controller 20 is a control device that selects a communication path in the mobile network 2. The path selection controller 20 corresponds to, for example, a Session Management Function (SMF), which is a network function (NF) that manages sessions in a 5G core network.

[0021] The UPF 21 is a network function that forwards user data packets in the 5G core network, and forwards U-plane data in accordance with settings from the path selection controller 20. The UPF 21 is an example of a communication path within the mobile network 2.

[0022] The GW 30 is a relay device that relays communication between the UPF 21 and the edge server 40. In the example of Fig. 9, a GW 30a-1 corresponding to the edge server 40a and a GW 30a-2 corresponding to the edge server 40b are provided for the UPF 21a. Similarly, a GW 30b-1 corresponding to the edge server 40a and a GW 30b-2 corresponding to the edge server 40b are provided for the UPF 21b.

[0023] In this case, since the number of required GWs increases as the number of connection destination edge servers 40 increases, there is a demand to build the communication system 1 without increasing the number of GWs as much as possible. For example, as shown in Fig. 10, it is conceivable to configure the communication system 1 with a small number of GWs 30 by accommodating connection destinations of multiple edge servers 40 in one GW 30.

[0024] 10 , it is assumed that the UE 10a uses the edge server 40a via the GW 30a. Also, it is assumed that the UE 20b uses the edge server 40b via the GW 30a. In this way, when the GW 30 has multiple connection destinations, with the conventional technology, even a single route failure may cause route switching for all of the connection destinations accommodated by the GW 30.

[0025] For example, in FIG. 10 , when a route failure 4 is detected on the route from the GW 30a to the edge server 40b, in the conventional technology, the route selection controller 20 removes the UPF 21a from the connection destination list. As a result, the connection destinations of the UEs 10a and 10b are changed from the UPF 21a to the UPF 21b. In this way, in the conventional technology, even though no route failure occurs on the route from the GW 30a to the edge server 40a, the UPF 21 used by the UE 10a is switched. If this switch causes, for example, the UPF 21 closest to the UE 10a to no longer be selected, delays may increase and the service quality of the edge server 40a may deteriorate.

[0026] The technology disclosed in Patent Document 1 makes it possible to switch routes even when a route failure occurs, but delay calculation is required for each service (edge ​​server), and information such as the edge server 40 and UPF 21 related to UE 10 must be set in advance.

[0027] As described above, in the conventional technology, in a communication system 1 in which a GW 30 accommodates connection destinations of multiple edge servers 40, when a route failure occurs, it is difficult to selectively detour a UE 10 using the route on which the route failure occurred to another GW 30.

[0028] Therefore, in this embodiment, in a communication system in which a GW 30 accommodates connection destinations of multiple edge servers 40, when a route failure occurs, it is made easy to selectively detour UEs 10 using the route on which the route failure has occurred to another GW 40.

[0029] <System Configuration> Fig. 1 is a diagram illustrating an example of the system configuration of a communication system according to this embodiment. In the example of Fig. 1, a communication system 100 includes UEs 10a and 10b, a route selection controller 120, UPFs 21a and 21b, GWs 130a and 130b, and edge servers 40a and 40b. In the following description, when referring to any GW among the GWs 130a and 130b, "GW 130" is used. Furthermore, the numbers of UEs 10, UPFs 21, GWs 130, edge servers 40, etc. illustrated in Fig. 1 are merely examples, and other numbers greater than or equal to two may also be used.

[0030] The UE 10 is an example of a communication terminal that communicates with the edge server 40 via the mobile network 2. The mobile network 2 is, for example, a mobile network such as 5G or LTE. Here, the following description will be given assuming that the mobile network 2 is a 5G mobile network, but the mobile network 2 may be a mobile network other than 5G.

[0031] The UPF 21 is a network function that forwards user data packets in the 5G core network, and forwards U-plane data in accordance with settings from the path selection controller 120. The UPF 21 is an example of a communication path within the mobile network 2. The edge server 40 is a server device that provides a predetermined service to the UE 10.

[0032] The GW (gateway) 130 is a relay device that relays communication between the UPF 21 and the edge server 40. The GW 130 has, for example, a computer configuration, and realizes each functional configuration as shown in FIG. 2 by executing a predetermined program on the computer included in the GW 130. In the example of FIG. 2, the GW 130 has each functional configuration such as a communication control unit 201, a registration unit 202, a detection unit 203, a notification unit 204, and a DB (Database) 131. Note that at least a part of each of the above functional configurations may be realized by hardware.

[0033] The communication control unit 201 executes a communication control process for controlling communication (packet transfer, etc.) between the UPF 21 and the edge server 40 .

[0034] When a packet passes through the GW (gateway) 130, the registration unit 202 executes a registration process to register information about the UE (communication terminal) 10 that is the sender of the packet and information about the edge server 40 that is the destination of the packet in the DB (database) 131.

[0035] 3 is a diagram illustrating an image of a DB according to this embodiment. The registration unit 202 registers, in a DB 131 as shown in FIG. 3, information (e.g., IP address) of the UE 10 that is the source of a packet passing through the GW 130 and information (e.g., IP address) of the edge server 40 that is the destination of the packet, in association with each other.

[0036] The detection unit 203 executes a detection process to detect a route failure that has occurred on the route to the edge server 40. For example, in FIG. 1, when the detection unit 203 of the GW 130a cannot communicate with the edge server 40b, the detection unit 203 can detect that a route failure has occurred on the route to the edge server 40b.

[0037] When the detection unit 203 detects a route failure on the route to the edge server 40, the notification unit 204 executes a notification process to notify the route selection controller 120 of information about the UE (communication terminal) 10 using the route where the route failure was detected. For example, in FIG. 1, when the detection unit 203 of the GW 130a detects a route failure on the route to the edge server 40b, the notification unit 204 acquires information about the UE 10 using the route where the route failure was detected from the DB 131a. For example, the notification unit 204 acquires information about the source UE 10b corresponding to the edge server 40b from the DB 131 as shown in FIG. 3. The notification unit 204 also notifies the route selection controller 120 of the acquired information about the UE 10. For example, the notification unit 204 notifies the route selection controller 120 of the route failure of the UE 10b.

[0038] The DB 131 is a database that stores, for example, as shown in FIG. 3, information on the UE that is the sender of a packet that has passed through the GW 130 and information on the edge server 40 that is the destination, in association with each other.

[0039] 2 is an example. For example, the DB 131 may be provided outside the GW 130. The registration unit 202 may be a communication history storage unit or the like that includes the functions of the DB 131.

[0040] 1 , we will continue to explain the system configuration of the communication system 100. The path selection controller 120 is a control device that selects a communication path in the mobile network 2. The path selection controller 120 corresponds to, for example, an SMF or the like, which is a network function that manages sessions in a 5G core network.

[0041] The route selection controller 120 according to this embodiment has, for example, a computer configuration, and realizes, for example, the functional configuration shown in Fig. 4 by executing a predetermined program on the computer included in the route selection controller 120. In the example of Fig. 4, the route selection controller 120 has a session management unit 401.

[0042] The session management unit 401 executes a session management process for managing sessions within the mobile network 2. Furthermore, the session management unit 402 according to this embodiment switches the communication path within the mobile network 2 used by the UE 10 to a communication path to a GW 10 other than the GW 130 that detected the path failure, among the multiple GWs 130, based on information about the UE 10 notified from the GW 130. For example, in FIG. 1 , when the session management unit 402 receives a notification of a path failure for the UE 10b from the notification unit 204 of the GW 130a, it switches the UPF 21a connected to the UE 10b to a UPF 21b other than the UPF 21 that detected the path failure.

[0043] For example, the session management unit 402 according to this embodiment controls the UE 10 using the route in which a route failure has been detected to reattach to the mobile network 2 based on the information of the UE 10 notified from the GW 130. Furthermore, when the UE 10 reattaches to the mobile network 2, the session management unit 402 assigns a communication route (UPF 21) to another gateway to the UE 10.

[0044] <Processing Flow> Next, the processing flow of the communication method according to this embodiment will be described.

[0045] 5 is a sequence diagram showing an example of processing in the communication system according to the present embodiment. This processing shows an example of processing when a path failure occurs in the communication system 100 according to the present embodiment as shown in FIG.

[0046] At the start of the processing in FIG. 5, as shown in FIG. 6, it is assumed that the UE 10a is communicating with the edge server 40a via the GW 130a, and the UE 10b is communicating with the edge server 40b via the GW 130a.

[0047] In step S501, the UE 10a communicates with the edge server 401a via the GW 130a.

[0048] In step S502, when a packet transmitted by the UE 10a passes through the GW 130a, the registration unit 202 of the GW 130a registers, in the DB 131, information about the UE 10a that is the source of the packet and information about the edge server 40a that is the destination of the packet.

[0049] In step S503, the UE 10b communicates with the edge server 401b via the GW 130a.

[0050] In step S504, when the packet transmitted by the UE 10b passes through the GW 130a, the registration unit 202 of the GW 130a registers, in the DB 131, information about the UE 10b that is the source of the packet and information about the edge server 40b that is the destination of the packet.

[0051] In step S505, for example, as shown in FIG. 6, it is assumed that a route failure 601 occurs on the route from the GW 130a to the edge server 40b, and the detection unit 203 of the GW 130a detects the route failure 601.

[0052] In step S506, the notification unit 204 of the GW 130a transmits the search query of the UE 10 to be switched to the DB 131a. Here, the DB 131a is the DB 131 corresponding to the GW 130a.

[0053] In step S507, the DB 131a responds to the notification unit 204 of the GW 130a with information about the UE 10b that uses the edge server 40b.

[0054] In step S508, the notification unit 204 of the GW 130a notifies the route selection controller 120 of the route failure of the UE 10b.

[0055] In step S509, the session management unit 401 of the route selection controller 120 transmits to the UPF 21a a session release request for the UE 10b that is using the route in which the route failure 601 has occurred. This session release request is an example of a process in which the session management unit 401 controls the communication terminal that is using the route in which the route failure has been detected to reattach to the mobile network based on the notified information of the communication terminal.

[0056] In step S510, the UPF 21a transmits a re-attach request to the UE 10b, requesting re-attachment.

[0057] In step S511, the UE 10b transmits an attach request to the route selection controller 120.

[0058] In step S512, the path selection controller 120 designates a UPF 21b that is different from the UPF 21a in which the path failure 601 occurs, for the UE 10b that requests attachment.

[0059] In step S513, the UE 10b switches from the UPF 21a to the UPPF 21b. As a result, in steps S514 and S515, the UE 10b and the UPF 21b establish a PDU (Packet Data Unit) session.

[0060] 5, for example, the UE 10b can use the edge server 40b via the UPF 21b as shown in Fig. 7. Furthermore, the UE 10a, in which no path failure has occurred, can continue to use the edge server 40a by using the UPF 21a.

[0061] Thus, according to this embodiment, in a communication system 100 in which a GW 130 accommodates connection destinations of multiple edge servers 40, when a route failure occurs, a UE 10 using the route on which the route failure occurred can be selectively diverted to another GW.

[0062] <Hardware Configuration Example> The GW 130 and the path selection controller 120 have, for example, the hardware configuration of a computer 800 as shown in Fig. 8. The GW 130 and the path selection controller 120 may be realized by a plurality of computers 800. Furthermore, the computer may be a virtual computer on a cloud, or the like.

[0063] 8 is a diagram illustrating an example of the hardware configuration of a computer. In the example of Fig. 8, a computer 800 includes a processor 801, a memory 802, a storage device 803, a communication device 804, an input device 805, an output device 806, a bus B, and the like.

[0064] The processor 801 is, for example, an arithmetic unit such as a CPU (Central Processing Unit) that executes predetermined programs to realize various functions. The memory 802 is a storage medium readable by the computer 800, and includes, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory). The storage device 803 is a large-capacity storage medium readable by the computer, and may include, for example, a HDD (Hard Disk Drive), an SSD (Solid State Drive), various optical disks, and a magneto-optical disk.

[0065] The communication device 804 includes one or more pieces of hardware (communication devices) for communicating with other devices via a wireless or wired network. The input device 805 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 806 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 805 and the output device 806 may be integrated into one device (e.g., an input / output device such as a touch panel display).

[0066] The bus B is commonly connected to the above components and transmits, for example, address signals, data signals, and various control signals, etc. The processor 801 is not limited to a CPU, and may be another processor such as a DSP (Digital Signal Processor), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0067] (Supplementary Note) The GW 130 and the path selection controller 120 in this embodiment may be realized not only by dedicated devices but also by a general-purpose computer. In this case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to realize the function. Note that the term "computer system" here includes hardware such as an OS and peripheral devices.

[0068] Furthermore, "computer-readable recording medium" includes various storage devices such as portable media such as flexible disks, optical magnetic disks, ROMs, CD-ROMs, and storage devices built into computer systems. Furthermore, "computer-readable recording medium" may also include devices that dynamically store a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and devices that store a program for a certain period of time, such as volatile memory within a computer system that serves as a server or client in such cases.

[0069] Furthermore, the above program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in a computer system, or may be one that is realized using hardware such as a PLD or FPGA.

[0070] <Effects of the embodiment> According to the present embodiment, in a communication system 1 in which a GW 130 accommodates connection destinations of a plurality of edge servers 40, when a route failure occurs, it becomes easy to selectively detour a communication terminal (UE 10) that uses the route in which the route failure has occurred to another GW 130.

[0071] For example, in the communication system 1 according to this embodiment, there is no need to calculate delay for each edge server or to pre-set information such as the edge server and UPF name related to the communication terminal, as in the technology disclosed in Patent Document 1.

[0072] Furthermore, according to the communication system 1 of this embodiment, it is possible to reduce the possibility that delays will increase and the service quality of the edge server will deteriorate due to the nearest UPF 21 not being selected.

[0073] Summary of Embodiments This specification discloses at least the following communication systems and communication methods: (Item 1) A communication system including a mobile network and multiple gateways connected to multiple edge servers, and a route selection controller that selects a communication route within the mobile network, wherein the gateway has a notification unit that, when a route failure is detected on a route to the edge server, notifies the route selection controller of information about a communication terminal using the route that detected the route failure, and the route selection controller has a session management unit that, based on the information about the communication terminal, switches the communication route within the mobile network used by the communication terminal using the route to a communication route to one of the multiple gateways that is different from the gateway that detected the route failure. (Item 2) The communication system described in Item 1, wherein the gateway has a registration unit that, when a packet passes through the gateway, registers information about the communication terminal that is a source of the packet and information about the edge server that is the destination of the packet in a database, and when the notification unit detects the route failure on the route to the edge server, obtains information about the communication terminal using the route from the database. (Clause 3) The communication system described in clause 1 or 2, wherein the session management unit controls the communication terminal using the route to reattach to the mobile network based on information about the communication terminal, and assigns the communication route to the other gateway to the communication terminal when the communication terminal reattaches to the mobile network.(4) A communication method in which, in a communication system including a mobile network and a plurality of gateways connected to a plurality of edge servers, and a route selection controller that selects a communication route within the mobile network, when the gateway detects a route failure on the route to the edge server, the gateway executes a notification process to notify the route selection controller of information about a communication terminal that uses the route that detected the route failure, and the route selection controller executes a session management process to switch the communication route within the mobile network used by the communication terminal that uses the route to a communication route to one of the plurality of gateways that is different from the gateway that detected the route failure, based on the information about the communication terminal.

[0074] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0075] 2 Mobile network (mobile network) 10, 10a, 10b UE (communication terminal) 21, 21a, 21b UPF 40, 40a, 40b Edge server 100 Communication system 120 Route selection controller 130, 130a, 130b GW (gateway) 131, 131a, 131b DB (database) 201 Communication control unit 202 Registration unit 203 Detection unit 204 Notification unit 401 Session management unit 800 Computer

Claims

1. A communications system comprising a mobile network and a plurality of gateways connected to a plurality of edge servers, and a route selection controller that selects a communications route within the mobile network, wherein the gateway has a notification unit that, when a route failure is detected on a route to the edge server, notifies the route selection controller of information about a communications terminal that uses the route that detected the route failure, and the route selection controller has a session management unit that, based on the information about the communications terminal, switches the communications route within the mobile network that is used by the communications terminal that uses the route to a communications route to one of the plurality of gateways that is different from the gateway that detected the route failure.

2. The communication system of claim 1, wherein the gateway has a registration unit that registers information about the communication terminal that sent the packet and information about the edge server that is the destination of the packet in a database when the packet passes through the gateway, and the notification unit, when detecting a route failure on the route to the edge server, obtains information about the communication terminal that uses the route from the database.

3. A communication system as described in claim 1 or 2, wherein the session management unit controls the communication terminal using the route to reattach to the mobile network based on information about the communication terminal, and when the communication terminal reattaches to the mobile network, assigns the communication route to the other gateway to the communication terminal.

4. A communications method in which, in a communications system including a mobile network and a plurality of gateways connected to a plurality of edge servers, and a route selection controller that selects a communications route within the mobile network, when the gateway detects a route failure on the route to the edge server, the gateway executes a notification process to notify the route selection controller of information about a communications terminal that uses the route that detected the route failure, and the route selection controller executes a session management process to switch the communications route within the mobile network used by the communications terminal that uses the route to a communications route to one of the plurality of gateways that is different from the gateway that detected the route failure, based on the information about the communications terminal.

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