Communication system

Abstract

This communication system in a mobile network provided with a plurality of network nodes comprises: a shared DB that stores a context of a terminal; and a termination device that is provided between a base station and the plurality of network nodes and distributes a signal from the terminal to either one of the network nodes.

Description

communication systems

[0001] The present invention relates to communication systems in mobile networks.

[0002] NG-Flex (Non-Patent Document 1) and S1-Flex (Non-Patent Document 2) are conventional technologies for load balancing access from UEs (User Equipments) to AMFs (Access and Mobility Management Functions), which are 5G core network nodes. These technologies enable selection of an AMF in consideration of load balancing when a UE is newly connected.

[0003] In addition, as a conventional technology for realizing so-called statelessness in which the AMF itself does not hold context information of each UE (UE identifier, state, communication history, etc.), there is UDSF (Unstructured Data Storage Function) (Non-Patent Document 3).

[0004] By using UDSF, an AMF can back up UE context to the UDSF, which allows the UE context to be shared among multiple AMFs. According to this technology, even if an AMF fails, another AMF can retrieve the UE context from the UDSF and perform call processing.

[0005] "5G; System Architecture for the 5G System", 3GPP TS 23.501 version 15.2.0 Release 15 (2018-06). Keisuke Suzuki et al., "Technology Supporting the Core Network (EPC) Accommodating LTE", NTT DOCOMO Technical Journal, Vol. 19, No. 1, pp. 32-36 (Apr. 2011). "5G; Unstructured data storage services", 3GPP TS 29.598 version 17.5.0 Release 17 (2022-05). "5G; NG-RAN; Architecture description", 3GPP TS 38.401 version 16.3.0 Release 16 (2020-11).

[0006] However, in the conventional technology, when an AMF failure occurs, each UE accommodated by that AMF starts transmitting signals to another AMF simultaneously, resulting in a problem of burst traffic due to the concentration of bursty access.

[0007] The present invention has been made in view of the above points, and aims to provide a technique for preventing the occurrence of burst traffic when an AMF fails.

[0008] According to the disclosed technology, there is provided a communication system in a mobile network having a plurality of network nodes, the communication system comprising: a shared DB that stores terminal context; and a terminal device provided between a base station and the plurality of network nodes, the terminal device distributing signals from the terminal to one of the network nodes.

[0009] According to the disclosed technology, it is possible to prevent burst traffic from occurring when an AMF fails.

[0010] FIG. 1 is a diagram for explaining an overview of NG-Flex. FIG. 1 is a diagram for explaining an example of a situation in which burst traffic occurs. FIG. 2 is a diagram showing a sequence when burst traffic occurs when an AMF fails. FIG. 2 is a diagram showing the architecture of a communication system according to an embodiment of the present invention. FIG. 3 is a diagram showing a schematic configuration of a communication system according to an embodiment of the present invention. FIG. 4 is a diagram showing an example of a processing sequence in a communication system according to an embodiment of the present invention. FIG. 5 is a diagram showing an example of a configuration of a communication system in Example 1. FIG. 6 is a diagram showing a processing sequence of the communication system in Example 1. FIG. 7 is a diagram showing an example of a configuration of a communication system in Example 2. FIG. 8 is a diagram showing an example of a configuration of a communication system in Example 2. FIG. 9 is a diagram showing an example of a hardware configuration of a device.

[0011] 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.

[0012] In the following, we will first explain the conventional technology and its problems in more detail, and then explain the technology according to this embodiment. Note that while the content of the conventional technology disclosed in the prior art documents is publicly known, the analysis of the conventional technology and the problems to be solved below are not publicly known.

[0013] (Regarding conventional technologies and issues) As described above, NG-Flex (Non-Patent Document 1) and S1-Flex (Non-Patent Document 2) are conventional technologies for load balancing access from UEs (User Equipments) to AMFs (Access and Mobility Management Functions), which are 5G core network nodes. These technologies enable selection of an AMF in consideration of load balancing when a UE is newly connected.

[0014] As an example of the above-mentioned conventional technology, an overview of NG-Flex will be described with reference to FIG. 1. NG-Flex is a technology that assigns gNBs (base stations) and TAs (Tracking Areas) to multiple AMFs. In the example of FIG. 1, each gNB belongs to two AMFs. The gNB selects one of multiple AMFs (one of the AMFs in the AMF Set) for each UE. With the NG-Flex configuration, call control is possible within the AMF Set without changing the AMF even if the TA to which the UE belongs changes. However, if the UE moves across AMF sets, the AMF is changed.

[0015] In the NG-Flex configuration, when a UE connects (initial registration), an AMF can be selected taking load balancing into consideration. However, if a failure occurs, another AMF is selected. Since the selected AMF does not have the UE context, the UE disconnects the existing call and makes a new connection again.

[0016] Furthermore, a conventional technology for realizing a stateless AMF is UDSF (Unstructured Data Storage Function) (Non-Patent Document 3).

[0017] By using UDSF, an AMF can back up UE context to the UDSF, which allows the UE context to be shared among multiple AMFs. According to this technology, even if an AMF fails, another AMF can retrieve the UE context from the UDSF and perform call processing.

[0018] Conventional technologies such as NG-Flex and S1-Flex can achieve load balancing for new calls, but they cannot achieve load balancing for re-access of existing calls (calls in progress).For this reason, even if the conventional technologies NG-Flex and UDSF are combined to avoid disconnecting existing calls when an AMF fails, when an AMF fails, UEs accommodated by that AMF start transmitting signals simultaneously to other AMFs, resulting in access concentration on a specific AMF and the occurrence of burst processing.

[0019] An example of a situation in which a burst occurs will be described with reference to Fig. 2. As shown on the left side of Fig. 2, in a situation in which 750 users are accommodated in AMF#1 and 750 users are accommodated in AMF#2, if a failure occurs in AMF#1 in S1 (step 1), the call of the UE connected to AMF#1 is released in S2.

[0020] Then, in S3 shown on the right side of Fig. 2, a registration request or a service request is sent to AMF#2 all at once. That is, when one AMF goes down, signals are sent all at once from each UE accommodated in that AMF to another AMF, causing burst traffic.

[0021] Figure 3 shows the sequence when burst traffic occurs when an AMF fails. AMF #1 and AMF #2 are each connected to the gNB via SCTP (Stream Control Transmission Protocol) (S10).

[0022] The gNB selects one AMF (here, AMF #1) from multiple AMFs connected via SCTP and sends an initial registration request from each UE to the AMF #1 (S11). At this time, the UE context is registered in the individual DB #1 of AMF #1. After that, messages from each UE are sent to the same AMF #1, and the UE context stored in the individual DB #1 is used (S12).

[0023] When a failure occurs in AMF #1, the gNB detects the failure (S13) and simultaneously releases all calls connected to AMF #1. As a result, all UEs accommodated in AMF #1 perform an initial registration procedure with AMF #2, resulting in burst traffic (S14).

[0024] (System configuration of this embodiment) A technology according to this embodiment for solving the above problems will be described below. In this embodiment, the AMF is made stateless, and an SCTP termination device is provided between the qNB and the AMF, which distributes signals from each UE to one of the AMFs without being aware of the AMF it accommodates.

[0025] With the above configuration, even if an AMF fails, it is possible to avoid concentration of accesses from UEs accommodated by the AMF on a specific AMF, prevent the occurrence of bursts, and avoid disconnection of existing calls. Hereinafter, a technique according to the present embodiment will be described with reference to the drawings.

[0026] The AMF is a network node having functions such as terminating the RAN interface, terminating the NAS (Non-Access Stratum), registration management, connection management, reachability management, and mobility management. The gNB may also be called a base station. The UE may also be called a terminal. The SCTP termination device may also be called a "termination device."

[0027] FIG. 4 shows the architecture (failure-resistant architecture) of the communication system according to this embodiment.

[0028] As shown in Figure 4, in this embodiment, even if a failure occurs in an AMF, the layers are separated into a User Data layer, an AMF (5G core application) layer, and a transport layer so that processing can continue in other AMFs without simultaneously releasing calls. Also, the AMF is made stateless. In other words, each AMF does not have a UE context, and the UE context is stored in a DB common to multiple AMFs.

[0029] FIG. 5 shows a schematic configuration for implementing the architectural concept shown in FIG.

[0030] Under the current standard, when the gNB confirms that the GUTI (temporary ID) issued during the registration process is set in the signal transmitted from the UE, it transmits the signal to the AMF that issued the ID.

[0031] In this embodiment, an SCTP (Stream Control Transmission Protocol) termination device 60 is provided that enables signals to be distributed to AMFs other than the AMF from which the ID was issued without modifying the gNB that performs the above operations.

[0032] In the example shown in FIG. 5, SCTP termination devices 60-1 to 60-n are provided between the gNB 10 and AMFs #1 to #n (30-1 to 30-n). UE context is stored in a DB (database) 40 common to AMFs #1 to #n. With the configuration shown in FIG. 5, for example, if AMF #1 fails, a UE 20 that was communicating (connected) using AMF #1 can continue communication using another AMF (AMF #2 in FIG. 5) without disconnecting the call. Even if a large number of UEs 20 are accommodated in AMF #1, the communications of the large number of UEs 20 are distributed to multiple AMFs other than AMF #1 through load balancing.

[0033] (Processing Sequence) An example of a processing sequence when using the architecture shown in Fig. 5 will be described with reference to Fig. 6. This sequence is a sequence using stateless AMF, and therefore may be referred to as a stateless AMF sequence.

[0034] In the following description, when multiple devices of the same type are described without distinction, they will be described by reference numerals rather than numbers such as #1, #2, etc. For example, when describing the common functions of AMF#1 (30-1) and AMF#2 (30-2), they will be described as "AMF 30."

[0035] In the example of Figure 6, in the initial state, gNB10 is connected to each of AMF#1 (30-1) and AMF#2 (30-2) via SCTP.

[0036] In S101, an initial registration procedure is performed based on a registration request message transmitted from each UE 20. In this embodiment, the SCTP termination device 60 can perform signal distribution without being aware of which AMF accommodates which UE. In other words, the SCTP termination device 60 can distribute signals to any AMF for each process.

[0037] 6, each UE 20 may be connected to AMF#1 (30-1) or AMF#2 (30-2). The UE context of the UE 20 is stored in the shared DB 40 by the AMF 30 that performs the registration process for the UE 20 (S102).

[0038] In S103, processing of an event such as session establishment or handover is performed. Since the SCTP termination device 60 performs signal distribution without being aware of the accommodating AMF, for example, an AMF different from the AMF that performed the registration processing of the UE 20 may perform event processing of the UE 20.

[0039] For example, after the AMF#1 (30-1) performs the registration process for the UE 20, the SCTP termination device 60 may transmit to the AMF#2 (30-2) the session establishment message transmitted from the UE 20. In this case, the AMF#2 (30-2) acquires the UE context of the UE 20 from the shared DB 40 (S104) and performs the process for establishing the session.

[0040] In the example of FIG. 6, a failure occurs in AMF#1 (30-1), and in S105 the SCTP termination device 60 detects the failure of AMF#1 (30-1).

[0041] In S106, the SCTP termination device 60 transmits a message related to the event processing to the AMF#2 (30-2) that is not malfunctioning. The AMF#2 (30-2) performs the event processing by acquiring the UE context from the shared DB 40.

[0042] As described above, even if a failure occurs in one AMF, if the remaining AMFs are not faulty, event processing and the like can be performed without disconnecting existing calls. In addition, since initial registration due to the failure is no longer necessary, the occurrence of burst traffic can be avoided.

[0043] (Functional Overview of SCTP Termination Device 60) Here, an outline of the functions of the SCTP termination device 60 that performs signal distribution without regard to the accommodated AMF will be described while clarifying the differences from existing technologies.

[0044] <About AMF UE NGAP ID> In existing standards, as disclosed in Non-Patent Document 4, the AMF issues an AMF UE NGAP ID as an ID for identifying a UE on N2 (NGAP; a protocol used between a qNB and an AMF). In addition, the gNB assigns the AMF UE NGAP ID to a UE-related N2 signal and transmits it.

[0045] On the other hand, in this embodiment, any AMF can process signals of any UE, and the signals are distributed among multiple AMFs. To this end, the SCTP termination device 60 selects the AMF to which a UE-related signal is to be sent without regard to the AMF UE NGAP ID. Furthermore, by making the AMF stateless, any AMF can process N2 signals of any AMF UE NGAP ID.

[0046] <About 5G-GUTI> Furthermore, as disclosed in Non-Patent Document 1, in the existing standard, a temporary ID, 5G-GUTI, is issued to a UE registered in 5GC.

[0047] In signal processing after the registration process (CM-Idle state, i.e., in the state where the Initial UE Message is sent), 5GC identifies the UE using 5G-GUTI instead of SUPI (Subscription Permanent Identifier) ​​or IMSI (International Mobile Subscriber Identity), which are subscriber identification numbers in the mobile network. This is to protect user information.

[0048] In addition, the gNB selects an AMF based on the 5G-GUTI issued to the UE and transmits the UE's signal to the target AMF. In addition, UE signals after the registration process are preferentially transmitted by the gNB to the AMF that performed the registration process.

[0049] As disclosed in Non-Patent Document 1, the configuration of 5G-GUTI is as follows.

[0050] <5G-GUTI> := <guami><5G-TMSI> GUTI is an abbreviation for "Globally Unique Temporary Identifier" and TMSI is an abbreviation for "Temporary Mobile Subscription Identifier".

[0051] GUAMI is an abbreviation for "Globally Unique AMF Identifier" and is a number that globally uniquely identifies an AMF. The structure of GUAMI is as follows:

[0052] <guami> := <mcc> <mnc><AMF Region ID><AMF Set ID><AMF Pointer>On the other hand, in this embodiment, any AMF can process a signal of any UE, and the signal is distributed among multiple AMFs. For this reason, the SCTP termination device 60 selects an AMF to which a UE-related signal is to be sent without being aware of GUAMI.

[0053] The configuration and operation of the communication system according to this embodiment will be described in detail below using examples.

[0054] (First embodiment: system configuration) In the first embodiment, a method in which an SCTP termination device 60 communicates with an AMF 30 by using a message distribution infrastructure 70 will be described.

[0055] 7 shows a configuration example of a communication system in Example 1. Note that the components of the "communication system" may not include a gNB and an AMF.

[0056] As shown in Figure 7, this communication system includes gNB10-1, gNB10-2, an SCTP termination device 60, AMF#1 (30-1), and AMF#2 (30-2). Figure 7 also shows a shared DB 40.

[0057] gNB10-1 and gNB10-2 are connected to the SCTP termination device 60 via SCTP.

[0058] The SCTP termination device 60 includes an SCTP termination unit #1 (61-1), an SCTP termination unit #2 (61-2), and a message distribution infrastructure 70.

[0059] The message distribution infrastructure 70 has a UL queue 71, a DL queue 72-1 for the SCTP termination unit #1 (61-1), and a DL queue 72-2 for the SCTP termination unit #2 (61-2).

[0060] AMF#1 (30-1) has a message processing thread 31-1, and AMF#2 (30-2) has a message processing thread 31-2.

[0061] The operation of each functional unit in the above configuration is as follows.

[0062] The SCTP termination unit 61 in the SCTP termination device 60 adds SCTP termination device information and gNB information to the NGAP signal and transmits a message having these. The message is stored (enqueued) in the UL queue 71.

[0063] The UL queue 71 is common to multiple AMFs (AMF#1 and AMF#2 in the case of FIG. 7 ). The AMF 30 polls the UL queue 71 using the message processing thread 31 to harvest messages. Harvesting messages from the UL queue 71 corresponds to the SCTP termination device 60 distributing messages to the AMF 30.

[0064] The message processing thread 31 in the AMF 30 stores information (e.g., UE context) acquired from the message in the shared DB 40. Furthermore, the message processing thread 31 reads information from the shared DB 40 as necessary, creates a message including the information, and stores the message in the DL queue 72.

[0065] A DL queue 72 is provided for each SCTP termination unit 61. For example, a message from AMF 30 to gNB 10-1 is enqueued from AMF 30 to DL queue 72-1 for SCTP termination unit #1.

[0066] The SCTP termination unit 61 polls the DL queue 72 corresponding to itself, and if a message is found, it harvests the message. The SCTP termination unit 61 transmits the harvested message to the gNB 10.

[0067] The message delivery infrastructure 70 monitors the queue status of each of the UL queue 71 and DL queue 72, and can add AMFs 30 (auto scaling) based on the message retention or load status (load status). Note that the actual auto scaling process may be performed by the message delivery infrastructure 70, or by an operation system that receives instructions from the message delivery infrastructure 70.

[0068] In the message distribution infrastructure 70, by providing a UL queue 71 common to multiple AMFs 30, the AMFs 30 are hidden from the SCTP termination unit 61. Therefore, the SCTP termination unit 61 does not need to be aware of the addition or removal of the AMFs 30.

[0069] (First Embodiment: Processing Sequence) Next, an example of a processing sequence in the communication system of the first embodiment (configuration of FIG. 7) will be described with reference to Fig. 8. Here, it is assumed that AMFs #1 to #n exist, and an example in which AMF #1 (30-1) fails will be described.

[0070] In steps S201 and S202, the UE 20 is connected to the AMF #1 (30-1) and is in the RM-REGISTERED state / CM-CONNECTED state. In step S203, a failure occurs in the AMF #1 (30-1).

[0071] When the SCTP termination device 60 detects a failure in the AMF#1 (30-1), it disconnects the AMF#1 (30-1). "Disconnecting" means, for example, cutting the communication path to the AMF#1 (30-1).

[0072] Therefore, the failure of AMF#1 (30-1) does not affect either gNB10 or UE20.

[0073] After that, a normal event not related to a failure occurs in the UE 20. Here, the event is assumed to be a PDU session establishment.

[0074] In S205, UE 20 transmits a message (RRC UL Transfer / 5GMM UL NAS Transport / 5GSM PDU Session Establishment Request) to gNB 10. gNB 10 creates a message (NGAP UL NAS Transport / 5GMM UL NAS Transport / 5GSM PDU Session Establishment Request) from the received message and transmits the message to SCTP termination device 60. In SCTP termination device 60, the message is stored in the UL queue 71 of the message distribution infrastructure 70 by SCTP termination unit #1 (61-1).

[0075] An AMF 30 other than AMF#1 (30-1) is selected as the AMF 30 that processes the signal of the UE 20. Note that which AMF 30 other than AMF#1 (30-1) is selected may be selected autonomously based on the timing of polling from the AMF 30 side, etc. Here, it is assumed that AMF#2 (30-2) is selected.

[0076] In S207, the SCTP termination device 60 transmits the message to the AMF#2 (30-2) from the UL queue 71. In S208, the AMF#2 (30-2) acquires the UE context of the UE 20 from the shared DB 40 and executes call processing for the UE 20.

[0077] In S209 and S210, a message (NGAP PDU Session Resource Setup Request / 5GMM DL NAS Transport / 5GSM PDU Session Establishment Accept) is sent from AMF #2 (30-2) to gNB 10 via SCTP termination device 60.

[0078] In S211, RRC Reconfiguration is executed between the UE 20 and the gNB 10. In S212, the gNB 10 transmits a message (NGAP PDU Session Resource Setup Response) to the SCTP termination device 60. The SCTP termination device 60 selects an AMF 30 other than the faulty AMF #1 (30-1) from among AMF #2 to #n. Here, it is assumed that AMF #2 (30-2) is selected.

[0079] In S213, the SCTP termination device 60 transmits the message to the selected AMF#2 (30-2) from the UL queue 71. In S214, the AMF#2 (30-2) acquires the UE context of the UE 20 from the shared DB 40 and executes call processing for the UE 20.

[0080] As described above, in the configuration of Example 1, even if AMF #1 fails, the failure does not affect either gNB 10 or UE 20, and no burst traffic occurs.

[0081] (Embodiment 2) Next, a description will be given of embodiment 2. In embodiment 2, a communication method between an SCTP termination device 60 and an AMF 30 using HTTP communication will be described.

[0082] Figure 9 shows an example configuration of a communication system in Example 2. As shown in Figure 9, this communication system has gNB10-1, gNB10-2, SCTP termination device #1 (60-1), SCTP termination device #2 (60-2), AMF #1 (30-1), and AMF #2 (30-2). Figure 9 also shows a shared DB 40.

[0083] The gNB 10-1 and the SCTP termination device #1 (60-1) are connected by SCTP. Similarly, the gNB 10-2 and the SCTP termination device #2 (60-2) are connected by SCTP.

[0084] The SCTP termination device #1 (60-1) and the SCTP termination device #2 (60-2) have an SCTP termination & LB unit 62-1 and an SCTP termination & LB unit 62-2, respectively.

[0085] AMF#1 (30-1) has a message processing thread 31-1, and AMF#2 (30-2) has a message processing thread 31-2.

[0086] The operation of each functional unit in the above configuration is as follows.

[0087] The SCTP termination & LB unit 62 in the SCTP termination device 60 includes an SCTP termination function and a load balancer (LB: load distribution function).

[0088] The SCTP termination & LB unit 62 adds SCTP termination device information and gNB information to the NGAP signal and creates an HTTP request (NTTPReq) including these.

[0089] Furthermore, the SCTP termination & LB unit 62 selects one AMF 30 from the multiple AMFs 30 by WRR (Weighted Round-robin), and transmits an HTTP request to the selected AMF 30. Regarding the method of weighting in the weighted round-robin, for example, a larger weight is assigned to an AMF 30 with a large processing capacity than to an AMF 30 with a small processing capacity.

[0090] In addition, the SCTP termination & LB unit 62 monitors the status of each AMF 30 (its IP address), and if a failure of an AMF 30 is detected, the SCTP termination & LB unit 62 excludes the AMF 30 from the selection targets.

[0091] Furthermore, the SCTP termination & LB unit 62 can perform auto scaling to increase or decrease the number of AMFs 30. When increasing or decreasing the number of AMFs, the SCTP termination & LB unit 62 can change the settings to add or delete individual IP addresses of the AMFs 30. Note that the actual processing such as auto scaling and adding IP addresses may be performed by the SCTP termination & LB unit 62, or may be performed by an operation system that receives an instruction from the SCTP termination & LB unit 62.

[0092] The AMF 30 includes a web server and waits for an HTTP request sent from the SCTP termination device 60. The received HTTP request is processed by a message processing thread 31.

[0093] Furthermore, the AMF 30 transmits a downstream signal as an HTTP request to the SCTP termination device 60 connected to the destination gNB 10. For this HTTP communication, a transmission path is set between the AMF 30 and the SCTP termination device 60. This situation is shown in Figure 10. The SCTP termination device 60 includes a web server, and the web server waits for and receives HTTP requests.

[0094] (Hardware Configuration Example) Any of the devices described in this embodiment (SCTP termination device 60, AMF 30, shared DB 40, message distribution infrastructure 70, etc.) can be realized by, for example, causing a computer to execute a program. This computer may be a physical computer or a virtual machine on the cloud.

[0095] That is, the device can be realized by executing a program corresponding to the processing performed by the device using hardware resources such as a CPU and memory built into a computer. The program can be recorded on a computer-readable recording medium (such as a portable memory) and stored or distributed. The program can also be provided via a network such as the Internet or email.

[0096] Fig. 11 is a diagram showing an example of the hardware configuration of the computer. The computer in Fig. 11 includes a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, and the like, all of which are interconnected via a bus B. The computer may further include a GPU.

[0097] The program that realizes the processing on the computer is provided by a recording medium 1001, such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 to the auxiliary storage device 1002 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, but may be downloaded from another computer via a network. The auxiliary storage device 1002 stores the installed program as well as necessary files, data, etc.

[0098] The memory device 1003 reads and stores a program from the auxiliary storage device 1002 when an instruction to start the program is received. The CPU 1004 realizes functions related to the device in accordance with the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network, etc. The display device 1006 displays a GUI (Graphical User Interface) or the like according to the program. The input device 1007 is composed of a keyboard, mouse, buttons, a touch panel, etc., and is used to input various operation instructions. The output device 1008 outputs the results of calculations.

[0099] As described above, according to the technology described in the present embodiment, even if an AMF fails, it is possible to prevent accesses of multiple UEs accommodated by the AMF from concentrating on a specific AMF. This makes it possible to prevent burst traffic from occurring and to avoid disconnecting existing calls.

[0100] The following additional notes are provided regarding the above-described embodiments.

[0101] <Additional Notes> (Additional Item 1) A communications system in a mobile network having a plurality of network nodes, comprising: a shared DB that stores terminal context; and a termination device provided between a base station and the plurality of network nodes, the termination device distributing a signal from the terminal to one of the network nodes. (Additional Item 2) The communications system according to Additional Item 1, wherein each of the plurality of network nodes is a stateless network node and obtains the terminal context from the shared DB. (Additional Item 3) The communications system according to Additional Item 1 or 2, wherein the termination device includes a termination unit and a message distribution infrastructure provided between the termination unit and the plurality of network nodes, the message distribution infrastructure having an UL queue common to the plurality of network nodes, the plurality of network nodes receiving a message transmitted from the base station by polling the UL queue. (Additional Item 4) The communications system according to Additional Item 1 or 2, wherein the termination device includes a load balancer and selects a network node to which a signal is to be transmitted using weighted round robin.

[0102] 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.

[0103] 10 gNB 20 UE 30 AMF 31 Message processing thread 40 Shared DB 60 SCTP termination device 61 SCTP termination unit 62 SCTP termination & LB unit 70 Message delivery infrastructure 71 UL queue 72 DL queue 1000 Drive device 1001 Recording medium 1002 Auxiliary storage device 1003 Memory device 1004 CPU 1005 Interface device 1006 Display device 1007 Input device 1008 Output device< / mnc> < / mcc> < / guami> ​< / guami>

Claims

1. A communications system in a mobile network having a plurality of network nodes, comprising: a shared DB for storing terminal context; and a termination device provided between a base station and the plurality of network nodes, the termination device distributing a signal from the terminal to one of the network nodes.

2. The communication system according to claim 1, wherein each of the plurality of network nodes is a stateless network node and acquires terminal context from the shared DB.

3. A communication system as described in claim 1 or 2, wherein the termination device includes a termination unit and a message distribution infrastructure provided between the termination unit and the plurality of network nodes and having a UL queue common to the plurality of network nodes, and the plurality of network nodes receive messages transmitted from the base station by polling the UL queue.

4. The communication system according to claim 1 or 2, wherein the end device includes a load balancer and selects a network node to which a signal is to be sent using a weighted round robin algorithm.