Communication system and communication method

Abstract

To perform stable congestion control when AMF becomes overloaded.SOLUTION: A communication system includes a first device, a second device connected to the first device via a predetermined connection method and communicating information with the first device, and a control device that gives instructions to the first device regarding a signal processing method, and the control device changes the amount of signal flowing into the second device by outputting a control signal to the first device that changes the amount of signal flowing into the second device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Interface specifications in an open radio access network (O-RAN) are described in Non-Patent Document 1. Non-Patent Document 1 describes a communication procedure between a Near-Real-Time (Near-RT) RIC and an E2 node using a RAN Intelligent Controller (RIC) Service.

[0003] Furthermore, Non-Patent Document 2 describes countermeasure specifications for when an overload occurs in the Control Plane of a 5G mobile core network. Non-Patent Document 2 describes that, with regard to N2 overload control used when the Access and Mobility Management Function (AMF) is overloaded, the 5G-Access Network (5G-AN) node suppresses signals to the AMF in accordance with instructions issued by the AMF to the AMF. Specifically, the AMF notifies the AN node that its own AMF is in an overload state by sending an "NGAP OVERLOAD START" message to the 5G-AN node. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] O-RAN, “WG3 E2GAP”, v02.02 [Non-patent document 2] 3GPP, “TS 23.501”, v17.6.0 Summary of the Invention [Problem to be solved by the invention]

[0005] In the conventional 5G specifications described above, when an AMF falls into an overload state (congestion state), the AMF itself in the overload state calculates parameters necessary for signal suppression. According to conventional technology, when an AMF falls into an overload state, the AMF itself performs overload control (congestion control), which may further strain the processing capacity of the AMF.

[0006] The present invention has been made in consideration of the above circumstances, and its purpose is to perform stable congestion control when the AMF falls into an overload state. [Means for solving the problem]

[0007] (1) One aspect of the present invention is AN node a first device; N2 interface are connected and communicate with each other Device and Access and Mobility Management Function (AMF) A communication system comprising a second device and a control device that gives instructions regarding a signal processing method for the first device, wherein the control device changes the amount of signal flowing into the second device by outputting a control signal to the first device that changes the amount of signal flowing into the second device. (2) In one aspect of the present invention, in the above-mentioned communication system, the control device acquires information regarding congestion in the second device, and changes the amount of signal flowing into the second device by outputting a control signal to the first device that changes the amount of signal flowing into the second device based on the acquired information. (3) In one aspect of the present invention, in the above-mentioned communication system, the first device is an E2 node, the control device is a RAN Intelligent Controller (RIC) having a Non-Real-Time RIC (Non-RT RIC) and a Near-Real-Time RIC (Near-RT RIC), the Non-RT RIC acquires information regarding congestion of the second device, and the Near-RT RIC outputs the control signal based on the information acquired by the Non-RT RIC. ( 4)One aspect of the present invention is that in the above-mentioned communication system, the Non-RT RIC makes a first determination regarding overload control based on information regarding congestion of the second device acquired, and the Near-RT RIC collects information regarding overload control of the second device from the first device, makes a second determination regarding overload control based on the collected information and the first determination result made by the Non-RT RIC, and outputs the control signal based on the second determination result. ( 5 ) One aspect of the present invention is that, in the above-mentioned communication system, the control device performs overload control of the second device by outputting to the first device a first control signal that changes the amount of signal flowing into the second device, the second device performs overload control of the second device by outputting to the first device a second control signal that changes the amount of signal flowing into the second device, and the control device performs overload control of the second device by outputting to the first device a third control signal that changes the amount of signal flowing into the second device based on instructions included in the first control signal and instructions included in the second control signal. ( 6 ) In one aspect of the present invention, in the above-described communication system, the control device sets either the first control signal or the second control signal as the third control signal. ( 7 In one aspect of the present invention, in the above-described communication system, the control device sets the latest instruction of the first control signal or the second control signal as the third control signal. ( 8 ) One aspect of the present invention is that in the above-mentioned communication system, the control device generates the third control signal, which is different from the first control signal and the second control signal, based on the first control signal and the second control signal. ( 9 ) One aspect of the present invention is AN node a first device; N2 interface are connected and communicate with each other Device and Access and Mobility Management Function (AMF)A communication method using a second device and a control device that controls information communication between the first device and the second device, the communication method including an acquisition step in which the control device acquires information regarding congestion in the second device, and an output step in which the control device outputs a control signal that changes the amount of signal flowing into the second device based on the acquired information. [Effects of the Invention]

[0008] According to the present invention, it is possible to obtain the effect of stably executing congestion control when the AMF falls into an overload state. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a communication system according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating a detailed configuration example of a communication system according to the present embodiment. [Figure 3] FIG. 4 is a sequence diagram showing a first operation example of the communication system according to the present embodiment. [Figure 4] FIG. 10 is a sequence diagram showing a second operation example of the communication system according to the present embodiment. [Figure 5] FIG. 10 is a sequence diagram showing a third operation example of the communication system according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Embodiment] First, the prerequisites for the embodiment will be described. In the embodiment described below, a method is proposed in which a communication system 1 according to the embodiment executes overload control on an interface defined by the O-RAN architecture. However, the embodiment is not limited to this example, and the communication system 1 may be widely used in communication systems other than those with the O-RAN architecture.

[0011] [Function Configuration] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] FIG. 1 is a diagram showing an example of the configuration of a communication system 1 according to an embodiment. The communication system 1 includes a control device 3, a first signal processing device 5, and a second signal processing device 6. The example shown in the figure shows an example in which one of each of the control device 3, the first signal processing device 5, and the second signal processing device 6 is provided. However, this embodiment is not limited to this example, and there may be multiple of each device. In the following description, the first signal processing device 5 may be referred to as the first device, and the second signal processing device 6 may be referred to as the second device.

[0013] As an example, the control device 3 is a RAN Intelligent Controller (RIC). The control device 3 may include a Near-RT RIC and a Non-RT RIC. Also, as an example, the first signal processing device 5 is an E2 Node, more specifically, may be an O-CU-CP. Also, as an example, the second signal processing device 6 is an Access and Mobility Management Function (AMF).

[0014] In the communication system 1, the first signal processing device 5 and the second signal processing device 6 are directly or indirectly connected by a predetermined connection method. The first signal processing device 5 and the second signal processing device 6 communicate information with each other. A signal to be processed in the communication system 1 passes through the first signal processing device 5 and the second signal processing device 6. Here, if a large amount of signals flow into the communication system 1, the second signal processing device 6 may fall into an overload state (congestion state). According to the communication system 1, in preparation for the case where the second signal processing device 6 falls into an overload state, the second signal processing device 6 is provided with a means for giving instructions related to a signal processing method to the first signal processing device 5.

[0015] The second signal processing device 6 has a means for transmitting a specific message to the first signal processing device 5. When the first signal processing device 5 receives a specific message from the second signal processing device 6, it performs processing such as refusing to perform part of the signal processing or distributing a signal to the signal sender to suppress signal transmission. By having such a means, the communication system 1 can reduce the amount of signals flowing from the first signal processing device 5 to the second signal processing device 6, and can alleviate the load on the second signal processing device 6 even if the second signal processing device 6 falls into an overload state. Note that a similar procedure is performed when restoring the signal processing method in the first signal processing device 5 that has been changed to its original state.

[0016] However, if an attempt is made to appropriately control the amount of signal suppression using the above-described overload control method, there is a risk that the processing capacity of the second signal processing device 6 that generates the messages will be further strained. Therefore, the communication system 1 performs further overload control using another control device 3 that controls the signal processing behavior of the first signal processing device 5.

[0017] The control device 3 is connected directly or indirectly to the first signal processing device 5. Note that the control device 3 does not need to be connected to the second signal processing device 6. The control device 3 controls the signal processing behavior of the first signal processing device 5 in accordance with its internal settings. Specifically, the control device 3 issues instructions regarding the signal processing method of the first signal processing device 5 by outputting a control signal to the first signal processing device 5. By the control device 3 controlling the signal processing behavior of the first signal processing device 5, the second signal processing device 6 that has fallen into an overload state does not need to generate a message itself, and it becomes possible to appropriately control the amount of signal suppression. Therefore, according to this embodiment, it becomes possible to appropriately control the amount of signals flowing into the second signal processing device 6 without straining the processing capacity of the second signal processing device 6.

[0018] The control device 3 may receive an instruction from another device or a person that identifies the control content and execute control in accordance with the received instruction. The instruction that identifies the control content may be a command or the execution of an Application Programming Interface (API). The control device 3 may also collect (acquire) information about the status of the first signal processing device 5 or the second signal processing device 6, or receive a notification, and reflect the information in the control content. The information about the status of the first signal processing device 5 or the second signal processing device 6 may specifically be information about congestion in the second signal processing device 6. The information about congestion in the second signal processing device 6 may more specifically be the resource usage rate, number of processed signals, processing time, alarm, etc. of the second signal processing device 6. The control device 3 outputs a control signal to the first signal processing device 5 that changes the amount of signals flowing into the second signal processing device 6 based on the acquired information. The control device 3 performs overload control (congestion control) of the second signal processing device 6 by outputting the control signal to the first signal processing device 5.

[0019] 2 is a diagram showing a detailed configuration example of a communication system according to this embodiment. With reference to the diagram, a detailed configuration example when the communication system 1 is applied to a mobile network will be described. In the example shown in the figure, the communication system 1 includes a control device 3, an E2 node (AN node) 51, an AMF 61, and User Equipment (UE) 7. The E2 node 51 is a specific example of the first signal processing device 5, and the AMF 61 is a specific example of the second signal processing device 6. In addition, in the example shown in the figure, the control device 3 is a RIC including a Non-RT RIC 31 and a Near-RT RIC 33.

[0020] The Non-RT RIC 31, the Near-RT RIC 33, and the E2 node 51 are components shown in the O-RAN architecture. The AMF 61 is a component of the 5G mobile core network. The UE 7 is a terminal device that uses the network. The control device 3 and the E2 node 51 are connected to each other via an O1 interface and an E2 interface. The E2 node 51 and the AMF 61 are connected to each other via an N2 interface.

[0021] The E2 node 51 is a logical node having an E2 interface. The E2 node 51 provides functions related to the radio access network (RAN). The Non-RT RIC 31 collects information about the Near-RT RIC 33 and the E2 node 51 and controls their behavior. Specifically, the Non-RT RIC 31 acquires information about congestion in the AMF 61. The Non-RT RIC 31 may be connected to an external device (not shown) and acquire information about an external network. The external network is, for example, a network to which the AMF belongs. Based on the information acquired by the Non-RT RIC 31, the Near-RT RIC 33 outputs a control signal that changes the amount of signal flowing from the E2 node 51 to the AMF 61.

[0022] An example of the operation of the communication system 1 according to this embodiment will be described below with reference to FIGS.

[0023] [First example of operation (basic form)] 3 is a sequence diagram showing a first operation example of the communication system according to this embodiment. The first operation example of the communication system 1 will be described with reference to the same figure. The first operation example is a basic form of this embodiment.

[0024] (Step S1) The external network 8 transmits information about the external network to the Non-RT RIC 31. The information about the external network is, for example, information about congestion in the AMF 61 in the mobile core network. The information about congestion in the AMF 61 may include information identifying the RAN node or AMF involved in the congestion (e.g., ID, address, or name), an alarm, time, the level of load (e.g., resource usage rate, number of processed signals, or processing time), the number of signal suppressions and signal suppression rate expected for congestion mitigation, the type of signal to be suppressed, S-NSSAIs to be signal suppressed, the number of signal suppressions and signal suppression rate for each S-NSSAI, and the type of signal to be suppressed. Note that the information transmitted from the external network 8 may be information instructed by manual operation (in other words, by a human hand). Examples of manual operation include executing a command and accessing an API.

[0025] The trigger for the external network 8 to transmit information to the Non-RT RIC 31 may be, for example, any timing, regular timing, etc. More specifically, any timing may be when an event occurs, etc. Furthermore, the Non-RT RIC 31 may request the external network 8 to transmit information at any timing.

[0026] (Step S2) Non-RT RIC 31 acquires information transmitted from external network 8. Non-RT RIC 31 makes a determination regarding overload control based on the acquired information (information regarding congestion in AMF 61). The determination made by Non-RT RIC 31 may be referred to as a first determination. If Non-RT RIC 31 determines that overload control is necessary, it outputs an instruction to Near-RT RIC 33 to perform overload control.

[0027] The instruction output from the Non-RT RIC 31 to the Near-RT RIC 33 may be performed using, for example, the A1 interface specified by O-RAN. The instruction may be, for example, to create, update, or delete a policy or a machine learning model in the Near-RT RIC 33. Furthermore, when issuing the instruction, the Non-RT RIC 31 may also include an operation to obtain the policy or machine learning model in the Near-RT RIC 33.

[0028] The policy may include one Scope indicating the scope of application, and one or more Statements indicating the content of the policy, etc. Items in the Scope may include a UE ID, a Group ID, a Slice ID, a QoS ID, a Cell ID, etc. Items in the Statement may include information identifying the RAN node or AMF involved in the congestion (e.g., ID, address, name, etc.), an alarm, time, the degree of load (e.g., resource usage rate, number of processed signals, processing time, etc.), the number of signal suppressions and signal suppression rate expected for congestion mitigation, the type of signal to be suppressed, S-NSSAIs subject to signal suppression, the number of signal suppressions and signal suppression rate for each S-NSSAI, and the type of signal to be suppressed, etc.

[0029] The Near-RT RIC 33 may provide the Non-RT RIC 31 and the like with information on the type of policy that can be accepted as an instruction for overload control.

[0030] (Step S3) The Near-RT RIC 33 acquires the above-described first determination result (i.e., an instruction for overload control) from the Non-RT RIC 31. Based on the instruction, the Near-RT RIC 33 instructs the E2 node 51 to perform overload control.

[0031] The instruction output from the Near-RT RIC 33 to the E2 node 51 may be performed using, for example, an E2 interface defined by O-RAN. The instruction may be performed using, for example, an E2 CONTROL service or an E2 POLICY service.

[0032] The content of the instruction may include information identifying the RAN node or AMF involved in the congestion (e.g., ID, address, name, etc.), alarm, time, degree of load (e.g., resource usage rate, number of processed signals, processing time, etc.), the number of signal suppressions and signal suppression rate expected to alleviate the congestion, the type of signal to be suppressed, the S-NSSAI to be subjected to signal suppression, the number of signal suppressions and signal suppression rate for each S-NSSAI, and the type of signal to be suppressed.

[0033] These procedures allow the E2 node 51 to perform overload control in accordance with the received instruction. For example, the E2 node 51 can reject some RRC connection request signals or distribute a signal to the source of the RRC connection request signal to suppress signal transmission.

[0034] [Second example of operation (REPORT trigger type)] 4 is a sequence diagram showing a second operation example of the communication system according to this embodiment. The second operation example of the communication system 1 will be described with reference to the same figure. The second operation example differs from the first operation example in that, in addition to the basic form described above, information collection is also performed.

[0035] Step S11 in Fig. 4 is the same as step S1 in Fig. 3. Step S12 in Fig. 4 is the same as step S2 in Fig. 3.

[0036] (Step S13) The Near-RT RIC 33 notifies the E2 node 51 that it has collected information. This transmission may be performed using, for example, the E2 interface defined by O-RAN. This transmission may be performed using, for example, the E2 REPORT service, the INSERT service, or the RIC Subscription defined in POLICY. This transmission may also include information indicating a trigger for the E2 node 51 to transmit information.

[0037] The information collected by Near-RT RIC33 includes, for example, event occurrence notifications, E2 node alarms, time, load level (e.g., resource usage rate, number of processed signals, processing time, etc.), number of processed signals by signal type, and overload control settings, etc., information related to overload control.

[0038] (Step S14) The E2 node 51 transmits information to the Near-RT RIC 33 based on the information transmitted from the Near-RT RIC 33. The transmission may use, for example, an E2 interface defined by O-RAN. The timing of the transmission of the information transmitted by the E2 node 51 may be, for example, after detecting the occurrence of an event that triggers transmission, specified in step S13. As another example, the transmission may be immediately after step S13, or may be at a timing defined in advance.

[0039] The information that E2 node 51 transmits includes, for example, event occurrence notifications, E2 node alarms, time, load level (e.g., resource usage rate, number of processed signals, processing time, etc.), number of processed signals for each signal type, and information related to overload control, such as overload control settings.

[0040] (Step S15) The Near-RT RIC 33 acquires information transmitted from the E2 node 51. In other words, the Near-RT RIC 33 collects information related to overload control of the AMF 61 from the E2 node 51. The Near-RT RIC 33 makes a determination regarding overload control based on the collected information and the result of the first determination made by the Non-RT RIC 31. The determination made by the Near-RT RIC 33 may be referred to as the second determination. The Near-RT RIC 33 outputs a control signal (overload control instruction) to the E2 node 51 based on the result of the second determination.

[0041] The instruction output from the Near-RT RIC 33 to the E2 node 51 may be performed using, for example, an E2 interface defined by O-RAN. The instruction may be performed using, for example, an E2 CONTROL service or an E2 POLICY service.

[0042] The content of the instruction may include information identifying the RAN node or AMF involved in the congestion (e.g., ID, address, name, etc.), alarm, time, degree of load (e.g., resource usage rate, number of processed signals, processing time, etc.), the number of signal suppressions and signal suppression rate expected to alleviate the congestion, the type of signal to be suppressed, the S-NSSAI to be subjected to signal suppression, the number of signal suppressions and signal suppression rate for each S-NSSAI, and the type of signal to be suppressed.

[0043] Here, the first determination made by the Non-RT RIC 31 includes a determination made by advanced analysis utilizing AI / ML. However, the first determination made by the Non-RT RIC 31 is not limited to a determination made by advanced analysis utilizing AI / ML, and may include a relatively simple determination such as a rule-based or policy-based determination. The rule-based determination may be a determination based on a simple rule, such as setting a signal suppression rate according to the CPU usage rate of the AMF 61. Furthermore, the processing performed by the Non-RT RIC 31 is performed at a relatively long cycle of approximately one second or more. On the other hand, the second determination made by the Near-RT RIC 33 is a high-speed determination with a control cycle of several tens of milliseconds, for example. According to this embodiment, by performing the first determination and the second determination, it is possible to perform appropriate overload control.

[0044] [Third operation example (when overlapping with NGAP OVERLOAD START from AMF)] 5 is a sequence diagram showing a third operation example of the communication system according to this embodiment. The third operation example shows an example of processing when overload control from the Near-RT RIC 33 and overload control from the AMF 61 overlap.

[0045] Step S21 in Fig. 5 is the same as step S2 in Fig. 3. Step S22 in Fig. 5 is the same as step S3 in Fig. 3.

[0046] (Step S23) The AMF 61 instructs the E2 node 51 to perform overload control. This instruction is, for example, N2 overload control specified by 3GPP. Specifically, the AMF 61 issues an overload control instruction to the E2 node 51 by NGAP OVERLOAD START / STOP on the N2 interface. This causes the AMF 61 to regulate the amount of signals flowing from the E2 node 51 to the AMF 61 in an attempt to reduce the load when AMF congestion occurs.

[0047] In the following description, the control signal output in response to an overload control instruction (step S22) from the Near-RT RIC 33 to the E2 node 51 may be referred to as a first control signal. Also, the control signal output in response to an overload control instruction (step S23) from the AMF 61 to the E2 node 51 may be referred to as a second control signal. In other words, the Near-RT RIC 33 performs overload control of the AMF 61 by outputting to the E2 node 51 a first control signal that changes the amount of signal flowing into the AMF 61. Also, the AMF 61 performs overload control of the AMF 61 by outputting to the E2 node 51 a second control signal that changes the amount of signal flowing into the AMF 61.

[0048] Here, the E2 node 51 may receive a control signal from either the Near-RT RIC 33 or the AMF 61 and perform overload control. Also, the E2 node 51 may receive control signals from both the Near-RT RIC 33 and the AMF 61 (i.e., overlapping overload control instructions). In such a case, the Near-RT RIC 33 performs appropriate overload control based on the instruction included in the first control signal acquired from the Near-RT RIC 33 and the instruction included in the second control signal acquired from the AMF 61. Specifically, the E2 node 51 performs overload control of the AMF 61 by outputting a third control signal based on the instruction included in the first control signal and the instruction included in the second control signal. The procedure for generating the third control signal will be described below.

[0049] (Step S24) The E2 node 51 reports to the Near-RT RIC 33 that an overload control instruction has been received from the AMF 61. This report may be made using, for example, the E2 interface defined by O-RAN.

[0050] (Step S25) The Near-RT RIC 33 receives the report of step S24 from the E2 node 51. The Near-RT RIC 33 compares the content of the overload control instruction by the Non-RT RIC 31 (first control signal) with the content of the overload control instruction by the AMF 61 (second control signal). Based on the comparison result, the Near-RT RIC 33 determines whether the behavior related to overload control of the E2 node 51 needs to be updated.

[0051] The Near-RT RIC 33 may determine whether to update, for example, in the following manner.

[0052] First, the first method will be described. The Near-RT RIC 33 compares the content of the overload control instruction by the Non-RT RIC 31 with the content of the overload control instruction by the AMF 61, adopts the instruction that increases (or decreases) the signal suppression rate of the overload control, and determines whether there is a change from the current instruction. If there is a change, the Near-RT RIC 33 determines that the behavior related to the overload control of the E2 node 51 needs to be updated. If the signal suppression rate differs for each S-NSSAI, etc., the Non-RT RIC 31 may compare the respective signal suppression rates and adopt the instruction that results in a higher (or lower) signal suppression rate for each element. Furthermore, parameters other than the signal suppression rate may also be used as the comparison target.

[0053] Next, a second method will be described. The Near-RT RIC 33 may compare the acquisition times of the overload control instruction (first control signal) by the Non-RT RIC 31 and the overload control instruction (second control signal) by the AMF 61, and adopt the instruction content of the one that issued the overload control instruction earlier (or later). That is, the Near-RT RIC 33 adopts either the first control signal or the second control signal as the third control signal. When adopting the instruction content of the one that issued the overload control instruction earlier, the Near-RT RIC 33 sets the instruction of the first control signal or the second control signal that it acquired first as the third control signal. When adopting the instruction content of the one that issued the overload control instruction later, the Near-RT RIC 33 sets the latest instruction of the first control signal or the second control signal as the third control signal.

[0054] Next, a third method will be described. The Near-RT RIC 33 and / or the AMF 61 may separately assign priority information to the overload control instruction and make a decision based on the priority. In this case, the overload control instruction (first control signal) by the Non-RT RIC 31 and the overload control instruction (second control signal) by the AMF 61 include priority information. The Near-RT RIC 33 compares the priority information included in the overload control instruction (first control signal) by the Non-RT RIC 31 with the priority information included in the overload control instruction (second control signal) by the AMF 61, and adopts the instruction content with the higher priority.

[0055] Next, a fourth method will be described. The overload control instructions of either the Near-RT RIC 33 or the AMF 61 may be given priority. For example, a case where priority is given to the Non-RT RIC 31 will be described. If the Near-RT RIC 33 has not received an overload control instruction from the Non-RT RIC 31 but has received an overload control instruction from the AMF 61, the Near-RT RIC 33 will adopt the instruction from the AMF 61. Furthermore, if an overload control instruction has been received from the Non-RT RIC 31, the Near-RT RIC 33 will maintain the overload control instruction from the Non-RT RIC 31 even if an overload control instruction has been received from the AMF 61. The same applies when priority is given to the AMF 61 side.

[0056] Next, a fifth method will be described. When the Near-RT RIC 33 receives an overload control instruction from the AMF 61, the Near-RT RIC 33 may report to the Non-RT RIC 31 that the AMF 61 has received the overload control instruction, and the Non-RT RIC 31 may determine whether or not to update the overload control instruction after taking into account the status of the external network 8. In other words, the third control signal may be generated by the Non-RT RIC 31.

[0057] (Step S26) If it is determined in step S25 that the overload control instruction is to be updated, the Near-RT RIC 33 constructs the content of the overload control instruction to be updated (i.e., generates a third control signal). As described above, the content constructed by the Near-RT RIC 33 may use either or both of the overload control instruction from the Non-RT RIC 31 and the content of the overload control instruction from the AMF 61. That is, the Near-RT RIC 33 may generate a third control signal that is different from the first control signal and the second control signal based on the first control signal and the second control signal.

[0058] The above-described sequence is an example, and for example, the procedure of step S25 and the procedure of step S26 may be interchanged. When the procedure of step S25 and the procedure of step S26 are interchanged, the overload control instruction content may be constructed first, and whether or not to update may be determined depending on whether or not the constructed result differs from the current overload control instruction content.

[0059] (Step S27) The Near-RT RIC 33 transmits the constructed overload control instruction content to the AMF 61. In other words, the Near-RT RIC 33 outputs the third judgment result (i.e., overload control instruction) constructed or generated by the above-described method to the E2 node 51, and issues an instruction to perform overload control using new parameters.

[0060] The instruction output from the Near-RT RIC 33 to the E2 node 51 may be performed using, for example, an E2 interface defined by O-RAN. The instruction may be performed using, for example, an E2 CONTROL service or an E2 POLICY service.

[0061] The content of the instruction may include information identifying the RAN node or AMF involved in the congestion (e.g., ID, address, name, etc.), alarm, time, degree of load (e.g., resource usage rate, number of processed signals, processing time, etc.), the number of signal suppressions and signal suppression rate expected to alleviate the congestion, the type of signal to be suppressed, the S-NSSAI to be subjected to signal suppression, the number of signal suppressions and signal suppression rate for each S-NSSAI, and the type of signal to be suppressed.

[0062] [Summary of the embodiment] According to this embodiment, the communication system 1 has the advantage that, by being equipped with a control device 3 (specifically, a Non-RT RIC 31 and a Near-RT RIC 33), it is possible to stably perform overload control (congestion control) on the E2 node 51 even if the AMF 61 falls into an overload state.

[0063] Furthermore, according to this embodiment, the amount of signals flowing into the second signal processing device 6 can be changed by issuing an instruction to the first signal processing device 5 using the control device 3, which is a device separate from the second signal processing device 6. Therefore, since processing by the second signal processing device 6 itself in a congested state is not required, the congestion alleviation means of the second signal processing device 6 can be executed with higher reliability even when the second signal processing device 6 is in a congested state.

[0064] This will enable improvements in the overall service quality of mobile communication systems, such as 5G systems, and will contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which is to "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0065] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present invention.

[0066] In addition, a computer program for realizing the functions of each of the above-described devices may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read and executed by a computer system. Note that the "computer system" here may also include hardware such as an OS and peripheral devices. In addition, "computer-readable recording medium" refers to writable non-volatile memory such as a flexible disk, optical magnetic disk, ROM, or flash memory, portable media such as a Digital Versatile Disc (DVD), or storage devices such as a hard disk built into a computer system.

[0067] Furthermore, "computer-readable recording medium" also includes a medium that stores a program for a certain period of time, such as a volatile memory (e.g., Dynamic Random Access Memory (DRAM)) within a computer system that serves as a server or client when the program is transmitted via a network such as the Internet or a communication line such as a telephone line. The program may also be transmitted from a computer system that stores the program in a storage device or the like to another computer system via a transmission medium or by transmission waves within the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has the function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may also be a program for implementing some of the functions described above, or may be a so-called differential file (differential program) that can implement the functions described above in combination with a program already stored in the computer system. [Explanation of symbols]

[0068] REFERENCE SIGNS LIST 1...communication system, 3...control device, 5...first signal processing device, 6...second signal processing device, 31...non-RT RIC, 33...near-RT RIC, 51...E2 node, 61...AMF, 7...UE, 8...external network

Claims

1. A communication system comprising: a first device which is an AN node; a second device which is an Access and Mobility Management Function (AMF) and is connected to the first device by an N2 interface to communicate information with each other; and a control device which gives instructions regarding a signal processing method for the first device, The control device outputs a control signal to the first device to change the amount of signal flowing into the second device, thereby changing the amount of signal flowing into the second device. Communication system.

2. The control device acquires information about congestion of the second device, and changes the amount of signal flowing into the second device by outputting a control signal to the first device that changes the amount of signal flowing into the second device based on the acquired information. The communication system of claim 1 .

3. the first device is an E2 node; the control device is a RAN Intelligent Controller (RIC) including a Non-Real-Time RIC (Non-RT RIC) and a Near-Real-Time RIC (Near-RT RIC); The Non-RT RIC obtains information about congestion of the second device. The Near-RT RIC outputs the control signal based on the information acquired by the Non-RT RIC.

3. The communication system according to claim 1 or 2.

4. The Non-RT RIC makes a first determination regarding overload control based on the acquired information regarding congestion of the second device; The Near-RT RIC collects information on overload control of the second device from the first device, performs a second determination on overload control based on the collected information and a first determination result performed by the Non-RT RIC, and outputs the control signal based on the second determination result. The communication system according to claim 3 .

5. the control device performs overload control of the second device by outputting a first control signal to the first device that changes the amount of signal flowing into the second device; the second device performs overload control of the second device by outputting a second control signal to the first device that changes the amount of signal flowing into the second device; The control device performs overload control of the second device by outputting a third control signal to the first device to change the amount of signal flowing into the second device based on an instruction included in the first control signal and an instruction included in the second control signal.

3. The communication system according to claim 1 or 2.

6. The control device selects either the first control signal or the second control signal as the third control signal. The communication system according to claim 5 .

7. The control device determines the latest instruction of the first control signal or the second control signal as the third control signal. The communication system according to claim 5 .

8. The control device generates the third control signal, which is different from the first control signal and the second control signal, based on the first control signal and the second control signal. The communication system according to claim 5 .

9. A communication method using a first device that is an AN node, a second device that is an Access and Mobility Management Function (AMF) and is connected to the first device by an N2 interface and performs information communication with the first device, and a control device that controls information communication between the first device and the second device, comprising: an acquisition step in which the control device acquires information regarding congestion of the second device; an output step in which the control device outputs a control signal for changing the amount of signal flowing into the second device based on the acquired information; A communication method comprising:

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