Artificial satellite, ground system, satellite communication system, and satellite communication method

Abstract

This artificial satellite comprises a recording device (43), a computer (41), and a communication device (45). The communication device (45) is provided with a beam control device (46) and a beam-forming device (47). The recording device (43) records information that indicates communication traffic between the communication device (45) and at least one of a plurality of gateways (20) deployed on the ground. The computer (41) derives a variable parameter for controlling the beam-forming device (47) so that, when there is a bias in communication traffic between each of the plurality of gateways (20), the bias in communication traffic between each of the plurality of gateways (20) is reduced, and transmits the derived variable parameter to the beam control device (46). The beam control device (46) receives the variable parameter derived by the computer (41) and controls the beam-forming device (47) on the basis of the received variable parameter.

Description

[Technical field]

[0001] The present disclosure relates to a satellite, a ground system, and a satellite communication system. , and Satellite communication method By law Regarding. [Background technology]

[0002] In satellite communication systems, as operational life on orbit becomes longer, flexible payloads that can dynamically respond to fluctuations in communication traffic that accompany changes in user needs over time are desired. In addition, research is underway to fully digitize satellite-mounted equipment and optimize variable parameters corresponding to the frequency, time, and space domains, thereby making maximum use of satellite resources. Cloud computing technology is also advancing. Furthermore, in order to reduce the burden on centralized processing methods due to the dramatic increase in data volume and faster communication speeds, and to increase speed through parallel processing, distribution of processing and the Internet of Things (IoT) are progressing. However, when implementing distribution of processing and IoT in ground systems installed on the ground, issues arise such as the increase in power consumption and the increase in heat emissions due to faster processing speeds. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 146750 Brochure Summary of the Invention [Problem to be solved by the invention]

[0004] In a satellite communications system employing a flexible payload according to conventional technology such as that disclosed in Patent Document 1, a terrestrial NOC (Network Operation Center) collects information indicating the communications traffic of multiple gateways, selects a means for optimizing the frequency domain, time domain, and space domain in order to reduce the bias in the communications traffic indicated by the collected information, derives optimal values ​​for variable parameters of the communications device based on the selected means, and transmits the derived optimal values ​​as command values ​​to the satellite. The present disclosure aims to reduce the burden on ground systems by deriving values ​​of variable parameters that control a beamforming device in an artificial satellite so as to reduce bias in communication traffic among multiple gateways. [Means for solving the problem]

[0005] The satellite according to the present disclosure includes: A recording device; A computer, Communication equipment and An artificial satellite comprising: The communication device includes a beam control device and a beam forming device, the recording device records information indicating communication traffic between the communication device and at least one of a plurality of gateways deployed on the ground; the computer derives, when there is a bias in communication traffic among each of the plurality of gateways, a value of a variable parameter that controls the beam forming device so as to reduce the bias in communication traffic among each of the plurality of gateways, and transmits information indicating the derived variable parameter value to the beam control device; The beam control device receives information indicating values ​​of variable parameters derived by the computer, and controls the beam forming device based on the values ​​of the variable parameters indicated by the received information. Effect of the Invention

[0006] According to the present disclosure, when there is a bias in the communication traffic between each of the multiple gateways, a computer included in the artificial satellite derives a value of a variable parameter that controls a beamforming device so as to reduce the bias in the communication traffic between each of the multiple gateways. Therefore, according to the present disclosure, by deriving a value of a variable parameter that controls a beamforming device in the artificial satellite so as to reduce the bias in the communication traffic between each of the multiple gateways, it is possible to reduce the burden on the ground system. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing an overview of a satellite communication system 1 according to a first embodiment. [Diagram 2] 1 is a diagram showing an example of the configuration of a satellite communication system 1 according to a first embodiment. [Diagram 3] 2 is a diagram showing an example of a hardware configuration of a geostationary satellite 30 according to the first embodiment. [Figure 4] FIG. 2 is a diagram showing an example of the hardware configuration of a terrestrial data center 90 according to the first embodiment. [Diagram 5] 1 is a diagram showing an example of the configuration of a satellite communication system 1 according to a first embodiment. [Figure 6] 1 is a diagram showing an example of the configuration of a satellite communication system 1 according to a first embodiment. [Figure 7] FIG. 13 is a diagram showing an example of a hardware configuration of a terrestrial data center 90 according to a modified example of the first embodiment. [Figure 8] FIG. 1 shows an example of the configuration of a satellite communication system 1 according to a second embodiment. [Figure 9] FIG. 1 is a diagram for explaining a satellite communication system 1 according to a second embodiment. [Figure 10] FIG. 1 is a diagram for explaining a satellite communication system 1 according to a second embodiment. [Figure 11] FIG. 1 is a diagram for explaining a satellite communication system 1 according to a second embodiment. [Figure 12] FIG. 1 is a diagram for explaining a satellite communication system 1 according to a second embodiment. [Figure 13] FIG. 13 is a diagram for explaining a mesh communication network according to a second embodiment. [Figure 14] FIG. 1 is a diagram for explaining a satellite communication system 1 according to a second embodiment. [Figure 15] FIG. 1 shows an example of the configuration of a satellite communication system 1 according to a second embodiment. [Figure 16] 11A to 11C are diagrams illustrating the effects of the second embodiment. [Figure 17] 11A to 11C are diagrams illustrating the effects of the second embodiment. [Figure 18] 11A to 11C are diagrams illustrating the effects of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In the description of the embodiments and the drawings, the same elements and corresponding elements are given the same reference numerals. Descriptions of elements given the same reference numerals are omitted or simplified as appropriate. Arrows in the drawings mainly indicate data flow or processing flow. Furthermore, "part" may be read as "circuit," "step," "procedure," "processing," or "circuitry" as appropriate. In this specification, an artificial satellite may be referred to simply as a satellite.

[0009] Embodiment 1 Hereinafter, the present embodiment will be described in detail with reference to the drawings.

[0010] ***Configuration Description*** FIG. 1 shows an overview of a satellite communication system 1. The satellite communication system 1 includes a geostationary satellite 30, a plurality of gateways 20, and a terrestrial data center 90. As a specific example, the geostationary satellite 30 includes an edge server 42. The geostationary satellite 30 can communicate with the gateway 20. Note that communication between the geostationary satellite 30 and the gateway 20 may be performed via a communication satellite. The geostationary satellites 30 may form a satellite constellation. The satellite communication system 1 may include an artificial satellite other than a geostationary satellite instead of the geostationary satellite 30. The gateway 20 is a communication device having a relay function and is typically operated by a communication carrier. The terrestrial data center 90 is a data center deployed on the ground, and is a specific example of a data center used in cloud computing. The terrestrial data center 90 can communicate with the geostationary satellite 30. Note that the communication between the terrestrial data center 90 and the geostationary satellite 30 may be performed via a relay device or the like. Also, each user on the earth 600 has a user device 91. Specific examples of the user device 91 include a relay device owned by a company or the like that is a user, or a mobile terminal owned by the user. The user device 91 is capable of communicating with the gateway 20. Note that communication between the user device 91 and the gateway 20 may be performed via a relay device or the like.

[0011] 2 shows an example of the configuration of a satellite communication system 1. The satellite communication system 1 is composed of a geostationary satellite 30, a terrestrial system 50, a terrestrial data center 90, and user equipment 91. Notations such as "-1" are used to distinguish between multiple elements. N, M, and L each represent a natural number. The ground system 50 includes a plurality of gateways 20, a tracking and control facility, a Network Operation Center (NOC), and a Security Operation Center (SOC). The user device 91B is typically used in BtoB (Business-to-Business). Typically, a company or the like that has a contract with a telecommunications carrier owns the user device 91B. The user device 91C is typically used in BtoC (Business-to-Consumer). Typically, an individual that has a contract with a telecommunications carrier owns the user device 91C. The ground data center 90 exists in a cloud provider network and is communicatively connected to at least one of the multiple gateways 20. The cloud provider network is a network used by a cloud computing provider. There may be multiple ground data centers 90, and each ground data center 90 may be communicatively connected to some of the multiple gateways 20. The geostationary satellite 30 includes a satellite bus system communication device that communicates with the tracking and control facility, a computer 41, an edge server 42, and a communication device 45. The communication device 45 includes a beam control device 46 and a beam forming device 47. The communication device 45 is also called a mission system communication device. BF is an abbreviation of beam forming. The edge server 42 is a server that communicates with the terrestrial data center 90, and corresponds to the edge server of the terrestrial data center 90. The edge server 42 includes a recording device 43. The edge server 42 does not necessarily have to include the recording device 43. The computer 41 and the edge server 42 may be configured integrally.

[0012] Fig. 3 shows an example of the hardware configuration of the geostationary satellite 30. The hardware configuration of the geostationary satellite 30 will be described with reference to Fig. 3. The geostationary satellite 30 includes a satellite control device 31, a communication device 32, a propulsion device 33, an attitude control device 34, and a power supply device 35. The geostationary satellite 30 may include components that realize various other functions, but FIG. 3 will explain the satellite control device 31, the communication device 32, the propulsion device 33, the attitude control device 34, and the power supply device 35.

[0013] The satellite control device 31 is a computer that controls the propulsion device 33 and the attitude control device 34, and includes a processing circuit. Specifically, the satellite control device 31 controls the propulsion device 33 and the attitude control device 34 in accordance with various commands transmitted from the ground system 50 and the like. The communication device 32 is a device that performs communication with the outside of the geostationary satellite 30 . The propulsion device 33 is a device that provides thrust to the geostationary satellite 30 and changes the speed of the geostationary satellite 30. The attitude control device 34 is a device for controlling attitude elements such as the attitude of the geostationary satellite 30, the angular velocity of the geostationary satellite 30, and the line of sight (Line Of Sight) of the geostationary satellite 30. The attitude control device 34 changes each attitude element to a desired direction. Alternatively, the attitude control device 34 maintains each attitude element in a desired direction. The attitude control device 34 includes an attitude sensor, an actuator, and a controller. The attitude sensor is a device such as a gyroscope, an earth sensor, a sun sensor, a star tracker, a thruster, and a magnetic sensor. The actuator is a device such as an attitude control thruster, a momentum wheel, a reaction wheel, and a control moment gyro. The controller controls the actuator according to measurement data of the attitude sensor or various commands from the ground system 50 or the like. The power supply unit 35 includes devices such as a solar cell, a battery, and a power control device, and supplies power to each device mounted on the geostationary satellite 30.

[0014] The processing circuit provided in the satellite control device 31 will be described. The processing circuit may be dedicated hardware, or a processor that executes a program stored in a memory. In the processing circuit, some functions may be realized by dedicated hardware, and the remaining functions may be realized by software or firmware. In other words, the processing circuit can be realized by hardware, software, firmware, or a combination of these. Specifically, the dedicated hardware is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination of these. ASIC is an abbreviation for Application Specific Integrated Circuit. FPGA is an abbreviation for Field Programmable Gate Array.

[0015] 4 shows an example of a hardware configuration of the terrestrial data center 90. The terrestrial data center 90 communicates with the geostationary satellite 30. The terrestrial data center 90 is connected to a ground-side communication device 810, and communicates with the geostationary satellite 30 via the ground-side communication device 810. The terrestrial data center 90 may include a mobile terminal. The configuration of each of the devices included in the gateway 20 and the geostationary satellite 30 may be similar to the configuration of the terrestrial data center 90.

[0016] The ground data center 90 includes a processor 710, as well as other hardware such as a main memory device 720, an auxiliary memory device 730, an input interface 740, an output interface 750, and a communication interface 760. The interfaces are denoted as IF in Fig. 4. The processor 710 is connected to other hardware via a signal line 770 and controls the other hardware.

[0017] The terrestrial data center 90 includes a control unit 711 as a functional element. The functions of the control unit 711 are realized by hardware or software. The control unit 711 executes processes according to instructions from a satellite communication program.

[0018] ***Explanation of Operation*** The operating procedure of the satellite communication system 1 corresponds to a satellite communication method. Moreover, a program that realizes the operation of the satellite communication system 1 corresponds to a satellite communication program. The satellite communication program is a general term for programs that run in each device included in the satellite communication system 1. The satellite communication program may be recorded on a non-volatile recording medium that is readable by a computer. Specific examples of the non-volatile recording medium include an optical disk or a flash memory. The satellite communication program may be provided as a program product.

[0019] <Operation Example 1 According to Embodiment 1> FIG. 5 shows a configuration example of the satellite communication system 1 according to this operation example. In this operation example, the recording device 43 records information indicating communication traffic between the communication device 45 and at least one of a plurality of gateways 20 deployed on the ground. When there is a bias in the communication traffic between each of the plurality of gateways 20, the computer 41 derives a value of a variable parameter that controls the beam forming device 47 so as to reduce the bias in the communication traffic between each of the plurality of gateways 20, and transmits information indicating the derived value of the variable parameter to the beam control device 46. The derivation of the value of the variable parameter is to obtain a setting value of the value of the variable parameter. The beam control device 46 receives the information indicating the value of the variable parameter derived by the computer 41, and controls the beam forming device 47 based on the value of the variable parameter indicated by the received information. As a specific example, the beam control device 46 changes the frequency, beam width, and pointing direction of the beam forming device 47 based on the received variable parameter.

[0020] In recent years, in order to accommodate the changing needs of users due to the increasing speed and capacity of communication satellites and the longer operation periods in orbit, communication equipment has become fully digitalized and flexible payload technology using digital beamforming technology has advanced. On the other hand, there is an increasing need for high-speed broadband satellite communication systems using High Throughput Satellites (HTS), which enable large-capacity communication by using beam control devices with broadband channelizers.

[0021] The purpose of this operation example is to build a space-based high-speed broadband satellite communication system by autonomously, dynamically, and timely monitoring and managing a communication device called a flexible payload under conditions where communication traffic changes by transferring at least a part of the resource management function conventionally performed in the ground system 50 to the orbit. The communication device called a flexible payload has flexibility regarding frequency allocation and service coverage.

[0022] In recent years, flexible payloads have been moving toward full digitalization, which ensures flexibility by changing frequency allocation, beam width, and line of sight through variable beam control using digital channelizers and digital beamforming. However, flexible payloads do not need to be limited to digital devices, and an inexpensive satellite communication system 1 may be constructed using a flexible payload that combines digital and analog devices.

[0023] Fluctuations in communication traffic are fluctuations in the amount of data sent and received. When there is a large deviation in the amount of data sent and received by each of the multiple gateways 20, the data rate can be leveled out by increasing the number of beam types so as to widen the frequency band directed to the gateways 20 with large amounts of data, or by increasing the number of beams per unit service area, thereby expanding the transmission capacity.

[0024] As an example of implementing the function of the geostationary satellite 30 monitoring communication traffic and managing the resources of the digital payload of the communication device 45 based on the monitoring results, a specific example of optimization control using an optimization algorithm will be described. In this example, first, the computer 41 monitors changes in the communication volume of each of the multiple gateways 20 deployed on the ground. Next, based on the monitoring results, the computer 41 flexibly controls the digital beam so as to optimally allocate resources such as the power and communication capabilities of the geostationary satellite 30, thereby leveling the data rates between each of the multiple gateways 20. As a specific example, the optimization algorithm is an algorithm that determines the values ​​of variable parameters that control the beamforming device 47.

[0025] Here, the beamforming technology is a technology for transmitting radio waves, sound waves, or ultrasound waves in a specific direction or receiving them from a specific direction. Known beamforming technologies include a technology for controlling the transmission power of each of a plurality of transmitting and receiving modules in an active phased array antenna (APAA) to control the direction and beam width of the transmission beam, and a technology for controlling the transmission power of each of a plurality of transmitting and receiving modules. Beamforming devices that perform beamforming by arranging a large number of feeds have also become known in recent years. A traveling wave tube amplifier (TWTA) or a solid state power amplifier (SSPA) is used as an amplifier in the beamforming device 47.

[0026] A channelizer that changes the routing of multiple channels is known as the beam control device 46. As a specific example, the channelizer selects multiple frequency bands such as the Ka band or the Ku band, or performs frequency control called frequency hopping that changes the center frequency and band to be used within the same frequency band. The channelizer also controls the beam width, direction, and power of the beamforming device.

[0027] In general communication resource management, resources of a digital payload are managed, but the communication device 45 according to this operation example may manage resources of an analog payload or a semi-digital payload that is a mixture of analog and digital.

[0028] By carrying out the operation of communication resource management conventionally carried out on the ground in the geostationary satellite 30 as in this operation example, it is possible to reduce the burden on the ground. Also, according to this operation example, the optimization management is adapted to the time-varying user needs, and the optimization management of communication traffic is autonomously carried out in space, thereby reducing the burden on the ground system 50.

[0029] <Operation Example 2 According to Embodiment 1> In this operation example, an edge server 42 is deployed on the geostationary satellite 30 to turn the geostationary satellite 30 into an IoT (Internet of Things) system, and part of the processing of the ground system 50 is distributed to the IoT-turned geostationary satellite 30, thereby aiming to reduce the amount of heat emitted by the ground system 50.

[0030] 6 shows a configuration example of a satellite communication system 1 according to this operation example. In this operation example, an edge server 42 of a terrestrial data center 90 deployed on the ground includes a recording device 43. This operation example is similar to operation example 1 according to the first embodiment.

[0031] (Cloud Computing Explained) As the amount of information increases with the advancement of the information society, the increase in power consumption and heat dissipation measures have become issues. In particular, in centralized systems, the increase in power consumption and heat dissipation measures for supercomputers and large-scale data centers have become serious issues. On the other hand, in space, heat can be released into deep space by radiation cooling. Therefore, a system is conceivable in which the satellite is equipped with a supercomputer or data center to realize a cloud environment, and only the necessary data is transmitted to users on the ground after processing in orbit. This system has the effect of maintaining a cloud environment and contributing to the SDGs (Sustainable Development Goals) on the ground by reducing greenhouse gas emissions on the ground. The edge server 42 mounted on the geostationary satellite 30 has at least some of the functions of cloud data centers that were previously installed on the ground, and by executing at least some of the processing of the cloud data center in orbit, it has the effect of contributing to reducing the processing burden on the ground. According to the conventional technology, in order to set the variable parameters of the flexible payload, traffic monitoring is performed on the ground, and analysis processing for optimization to reduce bias between gateways and variable parameter setting are performed on the ground and transmitted to the satellite. According to this operation example, the processing that was conventionally performed on the ground is performed autonomously in space, so the processing burden on the ground is reduced.

[0032] Also, according to this operation example, when communicating large volumes of data between the terrestrial data center 90 and the edge server 42 in geostationary orbit, the data rate between the gateways 20 is leveled, which has the effect of enabling high-speed, large-volume communication via multiple gateways 20. Furthermore, by transmitting information of the terrestrial data center 90 provided in the terrestrial cloud environment to the edge server 42 in orbit, it is possible to share information between the terrestrial data center 90 and the edge server 42, or to distribute information between the terrestrial data center 90 and the edge server 42.

[0033] <Operation Example 3 According to Embodiment 1> This operation example corresponds to an operation example that extends operation example 1 or 2 according to embodiment 1. The computer 41 according to this operation example derives the value of a variable parameter using an inference model that has learned the relationship between the communication traffic of each of the multiple gateways 20 and the value of the variable parameter. In this operation example, the terrestrial data center 90 is equipped with a software model that simulates the satellite communication system 1.

[0034] As machine learning technology such as deep learning using AI (Artificial Intelligence) advances, the computer 41 can realize many functions by equipping it with AI. The AI-equipped computer 41 monitors the communication traffic of the gateway 20 on orbit and performs optimal control of the full digital equipment in response to fluctuations in the monitored communication traffic. Meanwhile, research has been progressing in recent years in which cloud service providers apply a modeling method called SDN (Software Defined Network) to terrestrial assets, analyze changes in user needs, and apply a modeling method called VSN (Virtual Satellite Network) to satellite assets to optimize communication traffic in software according to changes in user needs. The software model equipped in the terrestrial data center 90 reflects the results of this research. The simulator included in the ground data center 90 uses the software model to analyze fluctuations in user needs, generates teacher data or a teacher model based on the analysis results, and uploads the generated teacher data or teacher model to the edge server 42. The computer 41 updates the optimization algorithm using the uploaded teacher data or teacher model. Therefore, the simulator can improve the performance of the AI ​​included in the computer 41 and the effect of machine learning.

[0035] An operation example of the satellite communication system 1 according to this operation example will be described. First, the ground data center 90 analyzes the variable parameters of the beamforming device 47, which are variable parameters for reducing bias in communication traffic among the multiple gateways 20, by simulation using a software model. Next, the terrestrial data center 90 derives values ​​of recommended parameters, which are appropriate variable parameters according to the time transition of user needs, based on the results of the analysis of the variable parameters, and transmits information indicating the derived recommended parameters and the results of the analysis of the variable parameters as teaching data to the edge server 42. A specific example of the information indicating the results of the analysis of the variable parameters is information indicating a bias in communication traffic between each of the multiple gateways 20, or information indicating the characteristics of the bias, such as the time period in which the bias occurs. Next, the computer 41 receives information indicating each of the recommended parameters derived by the ground data center 90 and the results of analyzing the variable parameters from the edge server 42, and generates an inference model by performing machine learning such as deep learning using the received information as training data.

[0036] Factors that cause fluctuations in communication traffic include the need to change beam control parameters on a large scale in real time, and as a specific example, the need for frequent parameter updates, such as when using communication satellites during disasters, etc. Another factor that may be considered is the need for annual parameter updates to accommodate changes in user needs during the design life of a geostationary satellite, which lasts for 15 years or more. Variable parameters for controlling the flexible payload include parameters corresponding to the frequency domain, the spatial domain, the time domain, and the like. The parameters corresponding to the frequency domain are parameters corresponding to changing the composition ratio according to changes in needs within frequency bands in which communication carriers and the like have frequency rights, such as P band, L band, S band, C band, X band, Ku band, Ka band, Q band, or V band. The parameters corresponding to the spatial domain are parameters corresponding to changing the ground service area by changing the beam width and the viewing direction of multiple beams. The parameters corresponding to the time domain are parameters for various purposes, such as real-time optimal control, adaptation to diurnal variations between day and night, adaptation to seasonal variations, and adaptation to yearly variations. Furthermore, when the communication target is a moving object, it is necessary to ensure service coverage according to the moving range of the moving object and to change the beam field of view. In order to handle these many variable parameters, it is reasonable for the computer 41 to be equipped with artificial intelligence, for the computer 41 to store in the edge server 42 the results of parameter control based on past communication resource management and the fluctuations in the traffic monitoring results associated with the parameter control results, and for the computer 41 to update the optimization algorithm through machine learning. The input to the inference model is information related to the communication traffic of each of the multiple gateways 20. As a specific example, the information is information indicating the bias of the communication traffic between each of the multiple gateways 20, or input information in the user needs change analysis. The input information in the user needs change analysis will be described using a specific example. When it is empirically understood that the user needs change with a strong correlation with the time transition, it is reasonable for the inference model to derive the value of the recommended parameter, which is an appropriate variable parameter according to the time transition of the user needs. As another specific example, if there is a change in an element that is strongly correlated with the number of users, such as a population change or a change in the regional distribution of population density, the optimal values ​​of the total communication amount and the beam pointing direction change. Therefore, it is reasonable to derive the value of the recommended parameter, which is an appropriate variable parameter according to the change in the element that is strongly correlated with the number of users. As another specific example, when the user needs change due to a change in the communication environment, such as the development of a new technology or the development of a social infrastructure, it is reasonable to derive the value of the recommended parameter, which is an appropriate variable parameter according to the user needs associated with the change in the communication environment. Therefore, when generating an inference model, the computer 41 may use, as part of the teacher data, input information in a user needs fluctuation analysis, such as information indicating time transitions of user needs, information indicating fluctuations in factors that have a strong correlation with the number of users, or information indicating fluctuations in the communication environment, instead of information indicating bias in communication traffic between each of the multiple gateways 20, as information related to the communication traffic of each of the multiple gateways 20. The inference model generated in this manner corresponds to an inference model that has learned the relationship between the communication traffic of each of the multiple gateways 20 and the values ​​of variable parameters. In addition, the ground data center 90 may generate the inference model.

[0037] <Operation Example 4 According to Embodiment 1> This operation example corresponds to an operation example that expands operation example 1 or 2 according to embodiment 1. In this operation example, the terrestrial data center 90 includes a software model that simulates the satellite communication system 1.

[0038] An operation example of the satellite communication system 1 according to this operation example will be described. First, the ground data center 90 analyzes variable parameters for reducing the bias in communication traffic among each of the multiple gateways 20 through a simulation using a software model. Next, the ground data center 90 generates an optimization algorithm to be used by the computer 41 based on the results of analyzing the variable parameters, and transmits information indicating the generated optimization algorithm to the edge server 42. Next, the edge server 42 receives the information indicating the optimization algorithm, and transmits the received information indicating the optimization algorithm to the computer 41 . Next, the computer 41 receives the information indicating the optimization algorithm, and replaces the optimization algorithm recorded in the recording device of the computer 41 with the received optimization algorithm.

[0039] ***Other configurations*** <Variation 1> In this embodiment, the functions of the control unit 711 are realized by software. As a modified example, the functions of the control unit 711 may be realized by hardware. Figure 7 shows this modified example.

[0040] The terrestrial data center 90 includes an electronic circuit 780 in place of the processor 710 . The electronic circuit 780 is a dedicated electronic circuit that realizes the functions of the control unit 711 . Specifically, the electronic circuit 780 is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a logic IC (Integrated Circuit), a GA (Gate Array), an ASIC, or an FPGA. The functions of the control unit 711 may be realized by one electronic circuit, or may be distributed across multiple electronic circuits. As another modification, some of the functions of the control unit 711 may be realized by the electronic circuit 780, and the remaining functions may be realized by software.

[0041] The processor 710, the electronic circuit 780, the main memory device 720, and the auxiliary memory device 730 are collectively referred to as a processing circuitry. That is, in the ground data center 90, the function of the control unit 711 is realized by the processing circuitry.

[0042] Embodiment 2 The following mainly describes the differences from the above-described embodiment with reference to the drawings. There is a need for a method for achieving on-demand content distribution and live video distribution using satellite communication lines. In this embodiment, a method is proposed for reducing terrestrial communication traffic by having a geostationary satellite equipped with an edge server and a regenerative repeater multicast content to users who have requested the content distribution. Here, the edge server is equipped with a database for storing data indicating content distribution requests collected by a low-earth orbit broadband constellation. In addition, this embodiment proposes a space data center in which a low-earth orbit constellation collects data indicating distribution requests, and a geostationary satellite multicasts content corresponding to the distribution requests by utilizing a regenerative repeater and beam control.

[0043] The satellite communications business is in a transitional period due to the emergence of full digital satellites. In the conventional satellite communications business, the mainstream business model was that broadcasters who produced content based on advertising revenues would use bent-pipe communications satellites to simultaneously broadcast to a wide area. On the other hand, in recent years, the spread of the Internet on the ground has led to a rapid increase in business models that distribute on-demand content and receive fee revenues from users, resulting in an increase in communications traffic. Therefore, there is growing expectation for the use of satellite communications using full digital satellites as a measure to alleviate communications traffic on the ground. However, currently, there is no established method for delivering on-demand content via satellite communication, so the inherent advantages of artificial satellites are not being utilized. Geostationary satellites have advantages such as the ability to broadcast simultaneously over a wide area, but they have weaknesses such as the need for huge antennas to enable direct two-way communication with smartphones. On the other hand, while the rapid development of low-orbit broadband constellations in recent years is expected to realize direct communication with smartphones, they are not good at simultaneously distributing large amounts of content over a wide area. This is because it is irrational to transmit the same content to a huge number of users individually using low-orbit broadband constellations, as it would require a huge number of repeated inter-satellite communications.

[0044] In the first place, the reason for the tightness of communication traffic on the ground due to the increase in on-demand users is the same as the fact that low-orbit broadband constellations are not good at simultaneously distributing data over a wide area. Therefore, simultaneous broadcasting by geostationary satellites is considered to be an effective measure to alleviate communication traffic on the ground. A specific example of easing communication traffic on the ground is when geostationary satellites distribute data to multiple edge servers that are distributed in a distributed manner, each edge server caches the distributed data, and each edge server distributes it to users in close distances. Therefore, in this embodiment, a method for rationally achieving on-demand content distribution by satellite communication is provided. As a specific example, first, a low-earth orbit broadband constellation collects data indicating a distribution request for on-demand content with ID (Identification) and uploads the collected data to a geostationary satellite. Next, each user device located in a wide area downloads the data from the geostationary satellite. This example makes it possible to utilize the advantages of both. If a geostationary satellite acts as an edge server to store ID-attached digital content and then plays back and relays the content in response to a distribution request, on-demand content distribution via satellite communication can be realized. When three or more geostationary satellites distributed in the longitude direction above the equator form a circular communication network by performing two-way communication, it is possible to realize on-demand content distribution services to the whole world. In this case, a space data center concept using a low-earth orbit broadband constellation in combination can realize live video distribution to the whole world.

[0045] Also, unlike the bent-pipe system used in broadcasting satellites, flexible payloads, which have advanced digitalization of onboard equipment, can realize simultaneous distribution in a variety of ways. As a specific example, the flexible payload allows for streamlining, such as distributing different contents to different regions and increasing the transmission capacity to regions where distribution requests are concentrated. Furthermore, when distributing a wide variety of contents over a wide area, if the transmission capacity is increased by expanding the communication band, distribution of individual contents can be realized in a short time. In this case, if various contents are distributed in a time-division manner, it is possible to reduce the user's waiting time for distribution to a level where they do not feel stressed. Thus, multicasting using a flexible payload allows for simultaneous distribution that is superior in quality and quantity to the bent-pipe system.

[0046] In the distribution of on-demand content, the stakeholders include content distribution companies, satellite operators, network operators, server operators such as cloud servers and edge servers, and low-earth orbit satellite communication operators. Here, the source of funds for the operation of the system related to the distribution is the fee income from users, and the operation of the system related to the distribution is established based on a mutual contractual relationship regarding the communication line usage fee and the server usage fee. Therefore, by each operator being equipped with a communication line usage monitor device and a server usage monitor device, in addition to clarifying the calculation basis for the payment and receipt of usage fees for each operator, each operator can obtain information that contributes to optimizing the system operation, such as the number and arrangement of edge servers, and the update frequency and storage period of content.

[0047] In recent years, there are high expectations for the use of AI in space. As a specific example, an AI computer installed on a satellite will perform machine learning to learn conditions and algorithms that contribute to optimizing the operation of a communication system, and then, based on the results of the machine learning, optimally deliver content through on-orbit beam control, which is expected to dramatically improve communication traffic on the ground.

[0048] Recently, new business models have emerged through joint ventures or teaming among multiple stakeholders. As a specific example, if all or some of the satellite operators, server operators, network operators, low-orbit broadband constellation operators, and content distributors engage in a space data center business and practice a business of implementing an on-demand content distribution method that automatically translates the spoken language contained in on-demand distribution content and distributes data including data showing the results of the automatic translation from the space data center, on-demand content can be distributed to all users around the world who are in areas where the development of digital communication infrastructure is lagging behind. Specific examples of on-demand distribution content are American Hollywood movies, Korean dramas, or Japanese animation works. On-demand content delivery and live video delivery are characterized in that the amount of data required for a delivery request is very small, and the number of delivery requests is huge. On the other hand, the amount of data per content delivery corresponding to a delivery request is large, and the same data is transmitted to a huge number of users. Furthermore, while there is a bidirectional relationship between a request and delivery, content delivery is characterized in that it is unidirectional. Therefore, it is considered reasonable to divide the roles so that the low-orbit broadband constellation handles the uplink corresponding to distribution requests, and the geostationary satellite, which is good at multicast, handles the downlink corresponding to distribution. Generally, satellite communications using geostationary satellites have the disadvantage of latency, but because both on-demand content distribution and live video distribution are one-way, latency of a few seconds is not a problem.

[0049] Specific examples of effective methods for charging for content that is broadcast simultaneously include a method in which data representing ID-attached content is encrypted so that only users who have paid and obtained an encryption key can decrypt the encrypted data, and a conventional method in which passwords are managed in a membership-based system by linking them to the user IDs of users who have paid. Recently, the price of communication satellites has been smashed because of the need to compete with terrestrial communication infrastructure. This is based on the assumption that the Internet line is simply via space, and is a pricing method for distributing large amounts of data content to each user a huge number of times. However, if we focus on an index of communication value that takes into account the efficiency of collection of communication line usage fees, which is the amount obtained by multiplying the number of users charged for content distributed in one simultaneous broadcast, then on-demand distribution by satellite has a communication value several orders of magnitude higher than on-demand distribution by terrestrial communication lines, including users in areas where terrestrial infrastructure is not well developed. Therefore, if on-demand delivery using space data centers were to be put to practical use, it would eliminate the enormous amount of unnecessary work that had previously occurred in terrestrial communication lines. Specific examples of unnecessary work include the transmission of the same content and repeated transmission between distant locations. Therefore, if on-demand delivery were to be put to practical use, the total amount of communication would drop dramatically, making it difficult to collect the fees for terrestrial communication lines, and it is believed that the competitiveness of terrestrial communication operators would decline relatively. Needless to say, the practical application of on-demand delivery from space data centers will be a paradigm shift in the direction that is favorable from the perspective of the SDGs, such as reducing energy loss. From this perspective, even if the costs required for construction appear to be high, the existence of space data centers is considered to be justified.

[0050] When the term "regenerative repeater" is used for a terrestrial mobile base station, the generation of the mobile communication system may be distinguished. When distinguishing the generation of the mobile communication system, the terrestrial mobile base station is, for example, a 4G (Generation) base station, eNB (evolved NodeB), or a 5G base station, gNB (next Generation NodeB). In this application, when the term "regenerative repeater" is used, there is no intention to distinguish between generations of mobile communication systems, and the regenerative repeater may be read as a "content regenerator."

[0051] ***Explanation of Operation*** <Operation Example 1 According to Embodiment 2> The processes executed in the satellite communication system 1 according to this operation example correspond to the processes constituting an on-demand content distribution method. FIG. 8 shows a specific example of the satellite communication system 1 according to this operation example. The artificial satellite according to this operation example communicates directly or indirectly with each upload device constituting the upload device group. The artificial satellite is a geostationary satellite 30 as a specific example. The upload device group is composed of at least one upload device existing on the ground. Each upload device constituting the upload device group is either an edge server 42 or a user device 91. When the artificial satellite indirectly communicates with a target upload device which is one of the upload devices constituting the upload device group, the artificial satellite communicates with the target upload device via the gateway 20. The artificial satellite includes a recording device 43, a computer 41, and a communication device 45, and is a geostationary satellite 30 as a specific example. The recording device 43 stores a distribution request DB (Database) 61, which is a database of data indicating distribution requests for identifier-associated content. The recording device 43 stores data indicating identifier-associated content uploaded to the recording device 43 via the communication device 45 by at least one of the upload devices constituting the upload device group. A specific example of this data is distribution content 62. The recording device 43 also stores in the distribution request DB 61 data indicating a distribution request for identifier-associated content uploaded to the recording device 43 via the communication device 45 by at least one of the upload devices constituting the upload device group. The distribution request DB 61 is made up of data indicating distribution requests, and is also called an ID-attached distribution request DB. The ID is synonymous with an identifier. The distribution content 62 is data indicating the distribution content, and is also called ID-attached distribution content. The computer 41 selects, as the selected upload device, the upload device that uploaded data indicating the target distribution request, which is a distribution request included in the distribution request DB 61, to the recording device 43. The computer 41 gives a distribution command to the communication device 45 to distribute data indicating the identifier-affixed content corresponding to the target distribution request via the replay relay device 72. The communication device 45 includes a receiving device 73 , a transmitting device 74 , a processing device 71 , and a regenerative repeater device 72 . The receiving device 73 receives data indicating identifier-added content uploaded by at least one of the upload devices constituting the upload device group. The receiving device 73 receives data from at least one of the gateway 20, the edge server 42, and the user device 91. The processing device 71 has a function of processing data. The processing device 71 converts the data received by the receiving device 73 into data in a format that can be stored in the recording device 43, and stores the converted data in the recording device 43. A specific example of the converted data is the distribution content 62. Based on the distribution command, the regenerative repeater 72 modulates data indicating the identifier-added content stored in the recording device 43 into a transmission signal. The regenerative repeater 72 may be a general regenerative repeater. The transmitting device 74 transmits to the selected upload device the transmission signal modulated by the replay repeater 72 as the identifier-added content corresponding to the target distribution request. Each of the computer 41, the edge server 42, and the recording device 43 may be a general-purpose computer.

[0052] In recent years, the demand for on-demand delivery of digital content has been rapidly increasing. Therefore, the communication traffic on the ground is increasing in a method of temporarily storing the content in a cloud server deployed on the ground or in each edge server 42 distributed on the ground and delivering the content to multiple users by specifying the destination. The temporary storage of frequently used content is called caching, and the distribution of content to multiple users after specifying the destinations is called multicast. As a measure to improve the communication environment on the ground, a system that delivers on-demand digital content via satellite communication, taking advantage of the wide area coverage of artificial satellites, is desired. In this operation example, ID-attached distribution content is cached in a recording device 43 provided on the artificial satellite, and multicast to a plurality of users in response to a content distribution request. Methods for distributing on-demand content include directly multicasting ID-attached content stored in a recording device 43 equipped on the satellite to users, and caching the content from the satellite to an edge server 42, which then multicasts it to users.

[0053] In recent years, as communication devices of artificial satellites have become fully digitalized, the artificial satellites can perform both communication via the gateway 20 and direct communication with the edge server 42 or the user device 91. Therefore, the edge server 42 may transmit data indicating the ID-attached content to the artificial satellite via the gateway 20, and the edge server 42 or the user device 91 may transmit data indicating the ID-attached content directly to the artificial satellite. Similarly, the user device 91 may transmit data indicating a delivery request for ID-attached content directly to the satellite, and the edge server 42 may collect the data indicating the delivery request and upload the collected data to the satellite. The replay repeater 72 edits the data indicating the ID-added content temporarily stored in the recording device 43 into the form of transmission data. The transmission device 74 multicasts the data edited by the replay repeater 72 to the distribution destination designated by the computer 41.

[0054] It should be noted that each of the edge server 42 and the user device 91 may be located on the ground or in space. The recording device 43 provided on the satellite is sometimes called an edge server 42.

[0055] <Operation Example 2 According to Embodiment 2> This operation example is an expanded version of operation example 1 according to embodiment 2, and corresponds to an example of an on-demand content delivery method. In this operation example, the target edge server, which is the edge server 42 constituting the upload device group, collects data indicating a distribution request from at least one user device 91 constituting the upload device group, and uploads the collected data directly or indirectly to the recording device 43 provided in the artificial satellite described in operation example 1 related to embodiment 2. The artificial satellite according to this operation example distributes identifier-attached content corresponding to data indicating a distribution request uploaded to the recording device 43.

[0056] Fig. 9 is a diagram for explaining the satellite communication system 1 according to this operation example. As shown in Fig. 9, this operation example is a method in which an edge server 42 collects data indicating a request for delivery of ID-attached content without using a low-earth orbit broadband constellation, and uploads the collected data to an artificial satellite.

[0057] <Operation Example 3 According to Embodiment 2> This operation example is an expanded version of operation example 1 according to embodiment 2, and corresponds to an example of an on-demand content delivery method. In this operation example, the target edge server 42, which is an edge server 42 constituting the upload device group, receives low-earth orbit satellite collected data from the low-earth orbit broadband constellation, and directly or indirectly uploads the received low-earth orbit satellite collected data to the recording device 43 provided in the artificial satellite described in operation example 1 according to embodiment 2. The low-earth orbit satellite collected data is data indicating a distribution request collected by the low-earth orbit broadband constellation from at least one user equipment 91 constituting the upload device group. The artificial satellite according to this operation example distributes identifier-attached content corresponding to data indicating a distribution request uploaded to the recording device 43.

[0058] Fig. 10 is a diagram for explaining a satellite communication system 1 according to this operation example. As shown in Fig. 10, the on-demand content delivery method according to this operation example is a method for collecting data indicating a delivery request for ID-attached content using a low-earth orbit broadband constellation, and uploading the collected data to a geostationary satellite 30. In addition, when neither the artificial satellite described in the operation example 1 according to the second embodiment nor the low-earth orbit satellite 80 constituting the low-earth orbit broadband constellation is equipped with a GEO-LEO (Geostationary Orbit-Low Earth Orbit) communication device, the method is a method for uploading data indicating a delivery request to a geostationary satellite 30 via an edge server 42 installed on the ground. The low-earth orbit satellite 80 may also function as the edge server 42 that collects data indicating a distribution request. The edge server 42 according to this operation example may also collect data indicating a distribution request from a user transmitted by direct communication of a smartphone. A low-earth orbit broadband constellation such as Starlink (registered trademark), which is currently being developed, is equipped with a communication device for communicating with the ground and a LEO-LEO (Low Earth Orbit-Low Earth Orbit) communication device, and therefore can collect data indicating a distribution request for ID-attached content from a user on the ground. However, since a low-earth orbit broadband constellation does not have a GEO-LEO communication device, data upload to the artificial satellite described in the operation example 1 according to the second embodiment is performed via an edge server 42 installed on the ground.

[0059] <Operation Example 4 According to Embodiment 2> This operation example is an expanded version of operation example 1 according to embodiment 2, and corresponds to an example of an on-demand content delivery method. In this operation example, the artificial satellite described in the operation example 1 according to the second embodiment is a geostationary satellite 30, and includes a GEO-LEO communication device. The GEO-LEO communication device executes communication between the geostationary satellite 30 and a low-earth orbit satellite 80. At least one low-earth orbit satellite 80 constituting the low-earth orbit broadband constellation includes a GEO-LEO communication device. The artificial satellite and the low-earth orbit broadband constellation are communicatively connected by a GEO-LEO communication line. The GEO-LEO communication line is a communication line between the geostationary satellite 30 and the low-earth orbit satellite 80. The low-earth orbit broadband constellation collects data indicating a distribution request from at least one user device 91 constituting an upload device group, and uploads the collected data to a recording device 43 included in the artificial satellite via the GEO-LEO communication line. The artificial satellite distributes identifier-attached content corresponding to the data indicating the distribution request uploaded to the recording device 43. The hardware configuration of the low-earth orbit satellite 80 is similar to that of the geostationary satellite 30 .

[0060] Fig. 11 is a diagram for explaining the satellite communication system 1 according to this operation example. As shown in Fig. 11, when the artificial satellite described in the operation example 1 according to the embodiment 2 and the low-earth orbit satellite 80 each have a GEO-LEO communication device, the low-earth orbit satellite 80 can directly upload data indicating a distribution request collected by the low-earth orbit satellite 80 to the artificial satellite. The low-earth orbit satellite 80 may also function as the edge server 42 that collects data indicating a distribution request. The edge server 42 may also collect data indicating a distribution request from a user transmitted by direct communication of a smartphone.

[0061] <Operation Example 5 According to Embodiment 2> This operation example corresponds to an extended operation example of operation example 4 according to the second embodiment. In this operation example, the space data center is composed of a geostationary satellite group and a low-earth orbit broadband constellation. The geostationary satellite group is composed of three or more artificial satellites described in the operation example 1 according to the second embodiment, which are distributed in the longitude direction. The recording device 43 of each artificial satellite that constitutes the geostationary satellite group is an edge server 42. Each artificial satellite that constitutes the geostationary satellite group is a geostationary satellite 30, and is equipped with a GEO-GEO communication device that performs bidirectional communication between adjacent artificial satellites in the equatorial orbit. Three or more artificial satellites that constitute the geostationary satellite group form a circular communication network in the equatorial orbit. At least one artificial satellite that constitutes the geostationary satellite group is equipped with a GEO-LEO communication device that performs communication between the geostationary satellite 30 and a low-earth orbit satellite 80. At least one low-earth orbit satellite 80 that constitutes the low-earth orbit broadband constellation is equipped with a GEO-LEO communication device. The geostationary satellite group and the low-earth orbit broadband constellation communicate with each other using the GEO-LEO communication device. The low-earth orbit broadband constellation collects data indicating a distribution request from at least one user equipment 91 constituting the upload device group, and uploads the collected data to a recording device 43 provided in an artificial satellite constituting the geostationary satellite group. The geostationary satellite group and the low-earth orbit broadband constellation implement the on-demand content distribution method described in Operation Example 4 according to the second embodiment.

[0062] When an artificial satellite functions as an edge server 42, in order to realize on-demand distribution of digital content to users around the world, it is reasonable to distribute the digital content cached in the edge server 42 directly to the users via the satellite communication line. Fig. 12 is a diagram for explaining the satellite communication system 1 according to this operation example. As shown in Fig. 12, if three or more artificial satellites in geostationary orbit perform two-way communication to form a circular communication network above the equator, and if the geostationary satellite group establishes communication with a low-orbit broadband constellation that forms a communication network with user devices 91 present all over the world, a communication network can be formed from an edge server 42 in geostationary orbit to users all over the world. Therefore, according to this operation example, it is possible to realize on-demand distribution of digital content to users all over the world.

[0063] FIG. 13 is a diagram for explaining a low-orbit broadband constellation according to this operation example. As shown in FIG. 13, a circular communication network and a mesh-shaped communication network are formed in the low-orbit broadband constellation. Specifically, the low-orbit broadband constellation has a plurality of orbital planes, and in each orbital plane, each low-orbit satellite 80 communicates with each of the low-orbit satellites 80 flying in front and behind it. In addition, the target orbit satellite communicates with an adjacent orbit satellite. The target orbit satellite is a low-orbit satellite 80 flying in a target orbital plane, which is one of a plurality of orbital planes. The adjacent orbit satellite is a low-orbit satellite 80 flying in an orbital plane adjacent to the target orbital plane.

[0064] The worldwide spread of the Internet and the increasing demand for digital content distribution have caused the problem of an increase and concentration of communication traffic. At present, it is considered that by promoting decentralization using edge servers 42 and other methods to alleviate load, it will be possible to further develop users and further increase demand. In order to rationally solve this problem, it is reasonable to configure edge servers 42 in a wide area and hierarchically in response to content distribution requests. For this reason, a space data center concept is effective, in which an artificial satellite equipped with edge servers 42 is placed at the top of the hierarchical structure and a communication network with user devices 91 located all over the world is constructed. Here, the communication network includes a low-earth orbit broadband constellation. The space data center is equipped with a regenerative repeater 72, and in response to a content distribution request, the content is distributed to users via a lower terrestrial edge server 42 in the hierarchical structure, thereby distributing the communication traffic load and operating the communication network. In this case, it is reasonable to upload data representing the content of the live distribution company to the space data center and distribute the uploaded data to the whole world in real time. Also, in order to cope with the increase in data volume due to the high definition of video content, it is reasonable to optimally control the communication spot beam according to needs by utilizing the flexibility of the digital payload mounted on the artificial satellite.

[0065] <Operation Example 6 According to Embodiment 2> This operation example corresponds to an extended operation example of operation example 4 according to the second embodiment. In this operation example, the space data center is composed of a geostationary satellite group and a low-orbit broadband constellation, as in the operation example 5 according to the second embodiment. Each artificial satellite constituting the geostationary satellite group is a geostationary satellite 30, and is equipped with a GEO-GEO communication device. The geostationary satellite group forms a circular communication network above the equator. In the low-orbit broadband constellation, a plurality of orbital planes are distributed in the longitude direction. A circular communication network is formed by each low-orbit satellite 80 orbiting in a low orbit in each of the plurality of orbital planes performing bidirectional communication with each low-orbit satellite 80 flying in front of or behind each low-orbit satellite 80, and a mesh-like communication network is formed in the low-orbit broadband constellation by each orbital plane of the plurality of orbital planes performing inter-orbit communication with other orbital planes. At least one artificial satellite constituting the geostationary satellite group is equipped with a GEO-LEO communication device. At least one low-orbit satellite 80 constituting the low-orbit broadband constellation is equipped with a GEO-LEO communication device. The geostationary satellite group and the low-orbit broadband constellation perform bidirectional communication using a GEO-LEO communication device. At least one low-orbit satellite 80 constituting the low-orbit broadband constellation includes an edge server 42. The low-orbit broadband constellation collects data indicating a distribution request from at least one user device 91 constituting the upload device group, and uploads the collected data to a recording device 43 provided in an artificial satellite constituting the geostationary satellite group. The artificial satellite and the low-orbit broadband constellation implement the on-demand content distribution method described in Operation Example 4 according to the second embodiment.

[0066] When communication traffic of a geostationary satellite 30 increases, it is effective to alleviate the communication traffic of the geostationary satellite 30 by distributing edge servers 42 on the orbit. Each low-earth orbit satellite 80 constituting the low-earth orbit satellite group is provided with a recording device 43 as an edge server 42, data indicating contents is uploaded from the ground to the edge server 42, the edge server 42 stores the uploaded data, and the edge server 42 uploads data indicating contents to the geostationary satellite 30 via a ring communication network and LEO-GEO communication as necessary, thereby enabling distributed management. Figure 14 is a diagram for explaining a satellite communication system 1 according to this operation example. In addition, when each low-earth orbit satellite 80 constituting a low-earth orbit satellite group is used as an edge server 42, it is reasonable for the low-earth orbit satellite group to adopt an orbit called the Dawndusk orbit, which is a sun-synchronous orbit with a local sun time of 06:00 or 18:00, and to configure the low-earth orbit satellite group to exhaust heat from the recording device 43, which generates a large amount of heat, in an anti-sunside manner. A method in which a low-earth orbit satellite 80 also functions as an edge server 42 is described in, for example, [Reference 1].

[0067] [Reference 1] International Publication No. 2022 / 065256 Brochure

[0068] <Operation Example 7 According to Embodiment 2> 15 shows a configuration example of a satellite communication system 1 according to this operation example. The satellite communication system 1 executes a live video content distribution method. The following mainly describes the differences from operation example 1 according to embodiment 2. In this operational example, the satellite 81 communicates directly or indirectly with each upload device that constitutes the upload device group. The communication device 45 includes a receiving device 73, a transmitting device 74, and a processing device 71. Each upload device constituting the upload device group is either an edge server 42 or a user device 91. When the artificial satellite 81 indirectly communicates with a target upload device that is one of the upload devices in the upload device group, the artificial satellite 81 communicates with the target upload device via the gateway 20. The recording device 43 stores a distribution request DB 61. The distribution request DB 61 is a database of data indicating distribution requests for identifier-attached live video content. The recording device 43 stores in the distribution request DB 61 data indicating a distribution request for identifier-attached live video content uploaded to the recording device 43 via the communication device 45 by at least one of the upload devices constituting the upload device group. The computer 41 selects, as the selected upload device, the upload device that uploaded data indicating the target distribution request, which is a distribution request included in the distribution request DB 61, to the recording device 43. The computer 41 gives a distribution command to the communication device 45 to distribute, via the processing device 71, data indicating the identifier-affixed live content corresponding to the target distribution request. The receiving device 73 receives data indicating identifier-attached live video content uploaded by at least one of the upload devices constituting the upload device group. The processing unit 71 modulates the data received by the receiving unit 73 into a transmission signal. The transmitting device 74 distributes to the selected upload device the transmission signal modulated by the processing device 71 as the identifier-added live video content corresponding to the target distribution request.

[0069] In a live broadcast service called live video distribution, content is distributed in real time to users who have requested live video content distribution. For this reason, the artificial satellite does not temporarily store the received data and then reproduces and relays it, but instead modulates the received data using a processing circuit to generate transmission data, and distributes the generated transmission data to the users who have requested the distribution. This satellite communication method is called the bent pipe method. In some cases, data indicating ID-attached live content is uploaded from the edge server 42 to the satellite 81, but the user may also upload the data directly to the satellite 81. Each of the edge server 42 and the user equipment 91 may be located on the ground or in space.

[0070] The communication traffic differs between multicast and live distribution, with the latter transmitting more communication traffic from satellites. However, this operation example has the effect of increasing the responsiveness of live distribution as the communication capacity of satellites expands in the future. Also, if the number of big users such as companies increases, the distribution of communication traffic may change.

[0071] In this operation example, a target edge server which is an edge server 42 constituting the upload device group may collect data indicating a distribution request from at least one user equipment 91 constituting the upload device group, and upload the collected data directly or indirectly to a recording device 43 provided in the artificial satellite 81. In addition, the artificial satellite 81 may distribute identifier-attached live video content corresponding to the data indicating the distribution request uploaded to the recording device 43.

[0072] In this operation example, the target edge server, which is an edge server 42 constituting the upload device group, may receive data indicating a distribution request collected by the low-earth orbit broadband constellation from at least one user equipment 91 constituting the upload device group as low-earth orbit satellite collected data from the low-earth orbit broadband constellation, and may upload the received low-earth orbit satellite collected data directly or indirectly to the recording device 43.

[0073] <Operation Example 8 According to Embodiment 2> This operation example corresponds to an extended version of operation example 7 according to the second embodiment, and corresponds to an embodiment of a live video content distribution method. In this operation example, the artificial satellite 81 is a geostationary satellite and may be equipped with a GEO-LEO communication device. At least one low-earth orbit satellite 80 constituting the low-earth orbit broadband constellation is equipped with a GEO-LEO communication device. The artificial satellite 81 and the low-earth orbit broadband constellation are communicatively connected by a GEO-LEO communication line. The low-orbit broadband constellation collects data indicating a distribution request from at least one user device 91 that constitutes a group of upload devices, and uploads the collected data to a recording device 43 provided on the artificial satellite 81 via a GEO-LEO communication line. The artificial satellite 81 distributes live video content with an identifier corresponding to the data indicating the distribution request uploaded to the recording device 43 .

[0074] <Operation Example 9 According to Embodiment 2> This operation example corresponds to an extended operation example of operation example 7 according to the second embodiment. The space data center according to this operation example is composed of a geostationary satellite group that is distributed in the longitude direction and a low-orbit broadband constellation. The geostationary satellite group is composed of four or more artificial satellites 81. The recording device 43 provided in each of the satellites 81 constituting the geostationary satellite constellation is an edge server 42. Each of the satellites 81 constituting the geostationary satellite constellation is a geostationary satellite 30 and is equipped with a GEO-GEO communication device. Three or more satellites 81 constituting the geostationary satellite constellation form a circular communication network above the equator. At least one of the satellites 81 constituting the geostationary satellite constellation is equipped with a GEO-LEO communication device. At least one low earth orbit satellite 80 that constitutes the low earth orbit broadband constellation is equipped with GEO-LEO communications equipment. The geostationary satellites and the low-earth orbit broadband constellation communicate using GEO-LEO communication equipment. The low-orbit broadband constellation collects data indicating a distribution request from at least one user device 91 that constitutes a group of upload devices, and uploads the collected data to a recording device 43 provided in an artificial satellite 81 that constitutes a group of geostationary satellites. The geostationary satellite group and the low-earth orbit broadband constellation implement the live video content distribution method described in the eighth operation example according to the second embodiment.

[0075] In order to realize live video distribution to users all over the world, it is reasonable to use the bent-pipe broadcasting function of a satellite to simultaneously distribute the video to all users in a wide area in real time. A communication satellite in geostationary orbit can receive data indicating content from a live video distribution user, modulate the data received in real time in orbit, and use the modulated data to perform live distribution to each user in a wide area using a bent-pipe broadcasting function. In addition, three or more geostationary satellites 30 can perform live distribution to the entire world via a circular communication network in geostationary orbit. However, for users in high latitude regions, including polar regions, there is a limit to the communication field of geostationary satellites, so for high latitude regions, it is reasonable to carry out live streaming via low-earth orbit broadband constellations.

[0076] <Operation Example 10 According to Embodiment 2> This operation example corresponds to an extended version of operation example 1 or operation example 7 according to the second embodiment. A communication device 45 according to this operation example includes a beam control device 46 and a beam forming device 47.

[0077] A communication device 45 equipped with a beam control device 46 and a beamforming device 47 can deliver content relatively efficiently to a selected gateway 20, a selected edge server 42, or a selected user equipment 91 using a high-capacity concentrated beam called a spot beam.

[0078] <Operation Example 11 According to Embodiment 2> This operation example corresponds to an extension of operation example 10 according to the second embodiment. At least some of the upload devices constituting the upload device group according to this operation example are mobile objects.

[0079] The use of the Internet on mobile objects such as ships or aircraft has become widespread, so that a mobile object can act as an edge server 42 to provide communication services to passengers, and a privately owned ship or aircraft can also act as a user. The satellite 81 equipped with a beam control device 46 is able to change the direction of the communication beam depending on the position of the mobile unit.

[0080] <Operation Example 12 According to Embodiment 2> This operation example corresponds to an extended operation example of the first operation example according to the second embodiment. The computer 41 in this operation example uses an inference model that has learned the relationship between the distribution of communication traffic of identifier-labeled content and time fluctuations in the multiple edge servers 42 that make up the upload device group, to analyze the priority order for distributing each of the multiple identifier-labeled content and the order in which each of the multiple identifier-labeled content is to be distributed to each upload device, and determines a sequence for distributing the content by beam control.

[0081] As the use of AI in space progresses, by using an inference model that learns the distribution of delivery requests for ID-attached content at each edge server 42 and the time fluctuations of that distribution, and predicts daily fluctuations, seasonal fluctuations, fluctuations in the composition ratio between the number of individual users and the number of corporate users, and future increases and decreases in ID-attached content requests due to the influence of events occurring on the ground, it will be possible to quickly and rationally deliver content through relay playback, thereby reducing the total amount of communication traffic and saving satellite resources such as electricity.

[0082] As the digital communications environment improves, the need for on-demand and live video distribution is growing, and there is a strong demand for wide-area, streamlined content distribution via satellite communications as a measure to alleviate the excessive communication traffic situation on the ground. As a result of the advancement of full digitalization and flexibility of communication satellites, communication satellites are now able to directly communicate not only with multiple gateways 20 deployed on the ground, but also with multiple edge servers 42 and multiple user devices 91. Furthermore, by equipping the communication device 45 with the beam control device 46 and the beamforming device 47, the communication device 45 can selectively communicate with the edge servers 42 and user devices 91 that are unevenly distributed over a wide area, and can transmit digital data quickly and rationally. To realize on-demand distribution by satellite communication, a configuration is required in which the recording device 43 stores data indicating ID-attached content, and the replay relay device 72 distributes the data stored in the recording device 43. Also, to realize on-demand distribution, a mechanism is required for collecting distribution requests for ID-attached content. Therefore, in operation example 1 according to embodiment 2, data indicating a distribution request for ID-attached content collected by edge server 42 used by a content distribution provider is stored in recording device 43, edge server 42 that has collected the most distribution requests is selected by computer 41, and the ID-attached content is distributed by replay relay device 72. There are various methods for determining whether each edge server 42 has collected many delivery requests. The method may be a method in which the content distributor determines in advance the number of requests as a criterion for determining whether the number of delivery requests is large or not, or a method in which a predetermined number of edge servers 42 are selected in descending order of the number of delivery requests collected by relative comparison between multiple edge servers 42.

[0083] <Operation Example 13 According to Embodiment 2> The space data center according to this operation example includes a geostationary satellite group, a low-earth orbit satellite group, and ground facilities. The geostationary satellite group is composed of three or more geostationary satellites 30 that are distributed in the longitude direction. The low-earth orbit satellite group is composed of a plurality of low-earth orbit satellites 80. The ground facilities operate and control each of the geostationary satellite group and the low-earth orbit satellite group. Each geostationary satellite 30 constituting the geostationary satellite group includes an edge server 42, a regenerative repeater 72, and a GEO-GEO communication device. The geostationary satellite group forms a circular communication network above the equator. At least one geostationary satellite 30 constituting the geostationary satellite group includes a GEO-LEO communication device. Each low-orbit satellite 80 constituting the low-orbit satellite group flies on one of a number of orbital planes that are distributed in the longitude direction. Each low-orbit satellite 80 orbiting in low orbit on each of the multiple orbital planes performs two-way communication with each low-orbit satellite 80 flying in front of or behind it to form a circular communication network, and each of the multiple orbital planes performs inter-orbit communication with other orbital planes to form a mesh communication network. At least one low-orbit satellite 80 constituting the low-orbit satellite group is equipped with a GEO-LEO communication device. At least one low-orbit satellite 80 constituting the low-orbit satellite group is equipped with an edge server 42. The geostationary satellites and the low earth orbit satellites carry out two-way communication using GEO-LEO communication equipment. The low-orbit satellite group collects data indicating a distribution request from at least one user device 91 that constitutes the upload device group, and uploads the collected data to a target edge server, which is an edge server 42 provided in a geostationary satellite 30 that constitutes the geostationary satellite group. Each upload device constituting the upload device group is either an edge server 42 or a user device 91. The geostationary satellite group distributes, to each upload device that has uploaded data indicating a distribution request to the target edge server, on-demand content corresponding to the distribution request indicated by the data uploaded by each upload device.

[0084] <Operation Example 14 According to Embodiment 2> In one embodiment of this operation example, the business device executes the on-demand content delivery method described in any one of operation examples 2 to 4 according to embodiment 2, and also includes a communication line usage monitor device. The communication line usage monitor device measures communication traffic of the on-demand content, and records data indicating the measurement results.

[0085] In one implementation of this operation example, the business device executes the on-demand content delivery method described in any one of operation examples 2 to 4 according to embodiment 2, and also includes a server usage monitor device. The server usage monitor device records data indicating the data volume of each on-demand content and the storage period of each on-demand content.

[0086] In one embodiment of this operation example, the business device includes a communication line usage monitor device and a server usage monitor device. The business device performs on-demand distribution in the space data center described in the operation example 13 of the second embodiment.

[0087] In one embodiment of this operation example, the recording device 43 includes a communication line usage monitoring device or a server usage monitoring device as a monitoring device. In this embodiment, the computer 41 updates the learning inference algorithm of the inference model by machine learning the output information of the monitoring device.

[0088] Stakeholders involved in on-demand content distribution include content distribution companies, satellite operators, network operators, server operators such as cloud servers or edge servers, and low-earth orbit satellite communication companies. The system for distributing on-demand content is funded by revenues from users, and the system is operated based on a contractual relationship based on communication line usage fees and server usage fees. Therefore, by each operator being equipped with a communication line usage monitoring device and a server usage monitoring device, the basis for calculating usage fees becomes clear. The information collected by each device is information that contributes to optimizing system operation, such as the number and arrangement of multiple edge servers 42, the frequency of content updates, and storage periods. Here, each of the communication line usage monitoring device and the server usage monitoring device executes processing based on an algorithm that is mutually transparent between operators regarding the distribution of on-demand content.

[0089] In addition, new business models have recently emerged through joint ventures or teamings between multiple stakeholders. If all or some of the satellite operators, server operators, network operators, low-orbit broadband constellation operators, and content distribution operators were to engage in a space data center business, and practice a business of distributing on-demand content from a space data center by using American Hollywood movies or Korean dramas, and Japanese animation works as on-demand distribution content, utilizing machine translation, and implementing an on-demand content distribution method, it would be possible to distribute on-demand content to all users around the world who live in areas where digital communication infrastructure is not well developed. In this case, a communication line usage monitor and a server usage monitor are effective for setting contract conditions according to the contributions of each of a plurality of businesses and for monitoring the actual activities.

[0090] <Operation Example 15 According to Embodiment 2> In one example of this operation example, the business device according to the operation example 14 according to the embodiment 2 includes an automatic translation device. The business device automatically translates a speech language included in on-demand content or live video content using the automatic translation device, and distributes data including the result of the automatic translation.

[0091] In one embodiment of this operation example, the replay repeater 72 according to the operation example 1 according to the second embodiment includes an automatic translation device. The automatic translation device performs automatic translation of the speech language included in each of the identifier-added contents. The replay repeater 72 modulates data indicating the result of the automatic translation into a transmission signal.

[0092] The content business device may perform the machine translation, but because machine translation has become more sophisticated, the satellite operator may perform the machine translation using a playback processing circuit of the artificial satellite. Note that automatic translation by an artificial satellite in orbit corresponds to the business device operating the satellite performing the machine translation.

[0093] <Operation Example 16 According to Embodiment 2> In this operation example, the content distribution business device includes a communication line usage monitor device and a server usage monitor device. The content distribution business device performs the on-demand content distribution method described in any one of the operation examples 2 to 4 according to the second embodiment, or the live video content distribution method described in the operation example 7 or 8 according to the second embodiment, thereby tallying up the communication line usage fee and the server usage fee.

[0094] <Operation Example 17 According to Embodiment 2> In this operation example, the network business device includes a communication line usage monitor device, which tallies up a communication line usage fee, which is a usage fee to be charged to a content business device that performs the on-demand content delivery method described in any one of operation examples 2 to 4 according to the second embodiment, or the live video content delivery method described in operation example 7 or 8 according to the second embodiment.

[0095] <Operation Example 18 According to Embodiment 2> In this operation example, the server business device includes a server usage monitor device, and charges a server usage fee as compensation for lending out the memory area of ​​at least one of the cloud server and the edge server 42. The server business device tallies the server usage fee to be charged to the content business device that performs the on-demand content distribution method described in any one of operation examples 2 to 4 according to the second embodiment, or the live video content distribution method described in operation example 7 or 8 according to the second embodiment.

[0096] <Operation Example 19 According to Embodiment 2> In this operation example, the space data center business apparatus is composed of all or some of the content business apparatus, network business apparatus, and server business apparatus that perform on-demand distribution in the space data center described in operation example 14 of embodiment 2.

[0097] <Operation Example 20 According to Embodiment 2> The business device according to this operation example is a business device constituting the space data center business device described in operation example 19 according to embodiment 2, and is any one of a content business device, a network business device, and a server business device.

[0098] <Operation Example 21 According to Embodiment 2> In one embodiment of this operation example, the ground equipment operates and controls the space data center described in any one of operation examples 5, 6, 9, and 14 according to embodiment 2. The configuration of the ground equipment may be the same as the configuration of the terrestrial data center 90.

[0099] In one implementation example of this operation example, the ground equipment controls the operation of the artificial satellite described in the operation example 1 or 7 according to the second embodiment.

[0100] <Operation Example 22 According to Embodiment 2> The low-earth orbit broadband constellation business device according to this operation example charges a communication line usage fee to a communication line usage business device of the low-earth orbit broadband constellation. The low-earth orbit broadband constellation business device includes a low-earth orbit satellite 80 equipped with a GEO-LEO communication device, and uploads data indicating a distribution request from a user by the on-demand content distribution method described in the operation example 4 according to the second embodiment.

[0101] ***Explanation of the Effects of the Second Embodiment*** FIG. 16 is a diagram for explaining conventional content distribution. FIG. 16 shows distribution from a terrestrial core server to a user. In conventional content distribution, content is stored in a core server deployed on the ground and distributed to users via terrestrial communication lines. In this case, content is also distributed individually to users in remote locations. Therefore, in conventional content distribution, there were issues with the concentration of load on the core server and the increase in communication traffic due to repeated long-distance communication.

[0102] One solution to this problem is to disperse multiple edge servers 42, pre-store (precast) content from a core server in each edge server 42, and distribute the content from each edge server 42 to nearby user devices 91. Figure 17 is a diagram explaining this solution. Figure 17 shows distributed distribution to users via terrestrial edge servers. This solution can distribute the load and reduce the number of long-distance communications.

[0103] In one example of the on-demand content delivery method according to the present embodiment, the functions of the core server are transferred to an edge server 42 provided in an artificial satellite, and precasting of content to each edge server 42 distributed on the ground is realized by simultaneous delivery (multicast) from the artificial satellite. FIG. 18 is a diagram for explaining this embodiment. FIG. 18 shows simultaneous delivery from the satellite to the terrestrial edge servers and distributed delivery from the terrestrial edge servers to users. According to this embodiment, the total amount of communication traffic can be reduced by eliminating the need to repeatedly perform long-distance communication in order to precast content from the core server to each edge server 42. The effect of improving communication traffic due to multicasting is considered to depend on the statistical distribution of the popularity of the contents. Here, there is an analysis result that the distribution of the top 20 popular contents accounts for 80% of the total distribution. When this analysis result is actually realized, if the top 20 contents are distributed simultaneously to edge servers 42 scattered over a wide area by the on-demand content distribution method according to the present embodiment and a distribution service is provided from each edge server 42 to nearby user equipment 91, the total amount of communication traffic corresponding to the long distance communication from the core server to each edge server 42 is reduced by 20%.

[0104] A specific example of a method of directly multicasting to users is a method in which user equipment 91, which has uploaded data indicating a distribution request for on-demand content, downloads data indicating a key for decrypting the on-demand content and data indicating a timetable showing a simultaneous distribution schedule for the content, and downloads the data to the storage of user equipment 91 in the same manner as video recording of BS (Broadcasting Satellite) broadcasting. Here, BS broadcasting requires a recording time that is the same as the playback time of the content. However, according to the on-demand content distribution method of this embodiment, the download time of the content is short. Therefore, according to this embodiment, there is an effect that a content distributor can distribute a wide variety of content. In addition, by increasing the frequency of distribution of popular content, the waiting time for users can be reduced.

[0105] Today's cinema complexes have multiple screens in the same facility, and attract customers by screening many popular contents simultaneously and repeatedly. Here, as the beam control function of artificial satellites has become more sophisticated, a cinema complex can be considered as an analogy to simultaneously distributing a wide variety of contents multiple times by utilizing the beam control function and using different frequencies, areas, and time periods. This analogy has the effect of increasing the options of on-demand contents that users can select and the freedom of the time period for receiving them. Furthermore, if distribution of content to the whole world by the on-demand content distribution method according to this embodiment becomes possible in the future at the same time as the premiere of a new movie, a wide variety of new movies can be distributed even in areas where facilities such as cinema complexes are not available and the number of contents that can be screened is limited. Furthermore, while movie theaters require a commitment to real time, digital content download time is short, so it is expected that the use of the on-demand content distribution method according to this embodiment will be more effective in attracting users.

[0106] Nowadays, home delivery systems have become more sophisticated, and many products purchased online can be delivered after waiting overnight. As an analogy to the home delivery system, a space data center can function as an automatic collection and delivery system in the home delivery system, collecting digital content in response to a digital content delivery request and simultaneously delivering the digital content at night when communication traffic is low. By communicating at night, users can save on communication costs. Home delivery systems are streamlined by having delivery personnel deliver a wide variety of content in different regions. On the other hand, the on-demand content delivery system according to this embodiment has the effect of streamlining the delivery system by having artificial satellites deliver the delivery personnel over a wide area.

[0107] In the current on-demand content distribution business, users pay a communication fee to a communication carrier in addition to paying a fee for the content. On the other hand, if a business operator who develops a business related to the on-demand content distribution method according to the present embodiment creates an investment recovery model by charging for content, which collects fees including an on-orbit server usage fee and a communication line usage fee, the business operator can realize a highly competitive user charging model by improving the efficiency by satellite multicast.

[0108] ***Other embodiments*** Although the first embodiment has been described, it is possible to combine a plurality of parts of the present embodiment. Alternatively, it is possible to partially implement the present embodiment. In addition, the present embodiment may be modified in various ways as necessary, and may be implemented in any combination, either as a whole or in part. The above-described embodiment is essentially a preferred example, and is not intended to limit the scope of the present disclosure, its applications, and uses. The described procedure may be modified as appropriate. [Explanation of symbols]

[0109] 1 satellite communication system, 20 gateway, 30 geostationary satellite, 31 satellite control device, 32 communication device, 33 propulsion device, 34 attitude control device, 35 power supply device, 41 computer, 42 edge server, 43 recording device, 45 communication device, 46 beam control device, 47 beam forming device, 50 ground system, 61 distribution request DB, 62 distribution content, 71 processing device, 72 regenerative relay device, 73 receiving device, 74 transmitting device, 80 low-earth orbit satellite, 81 artificial satellite, 90 ground data center, 91, 91B, 91C user equipment, 600 earth, 710 processor, 711 control unit, 720 main memory device, 730 auxiliary memory device, 740 input interface, 750 output interface, 760 communication interface, 770 signal line, 780 electronic circuit, 810 ground side communication device.

Claims

1. A recording device; A computer, Communication equipment and An artificial satellite comprising: The communication device includes a beam control device and a beam forming device, the recording device records information indicating communication traffic between the communication device and at least one of a plurality of gateways deployed on the ground; when there is a bias in the communication traffic between each of the plurality of gateways, the computer derives a value of the variable parameter so as to reduce the bias in the communication traffic between each of the plurality of gateways using an inference model that has learned a relationship between the bias in the communication traffic between each of the plurality of gateways and a value of a variable parameter that controls the beam forming device, and transmits information indicating the derived value of the variable parameter to the beam control device; The beam control device is a satellite that receives information indicating the value of the variable parameter derived by the computer, and controls the beam forming device based on the value of the variable parameter indicated by the received information.

2. An edge server in a terrestrial data center deployed on the ground; A recording device; A computer, Communication equipment and An artificial satellite comprising: The edge server includes the recording device, The communication device includes a beam control device and a beam forming device, the recording device records information indicating communication traffic between the communication device and at least one of a plurality of gateways deployed on the ground; when there is a bias in the communication traffic between each of the plurality of gateways, the computer derives a value of the variable parameter so as to reduce the bias in the communication traffic between each of the plurality of gateways using an inference model that has learned a relationship between the bias in the communication traffic between each of the plurality of gateways and a value of a variable parameter that controls the beam forming device, and transmits information indicating the derived value of the variable parameter to the beam control device; The beam control device is a satellite that receives information indicating the value of the variable parameter derived by the computer, and controls the beam forming device based on the value of the variable parameter indicated by the received information.

3. 3. The satellite according to claim 1, wherein the satellite is a geostationary satellite.

4. The communication device is a fully digital device, 3. The artificial satellite according to claim 1 or 2, wherein the computer controls the communication device based on an optimization algorithm, which is an algorithm for implementing optimal control of a fully digital device in response to fluctuations in communication traffic, and which is an algorithm updated based on the results of analyzing fluctuations in user needs.

5. 5. The satellite according to claim 4, wherein the optimization algorithm is an algorithm generated based on a result of analyzing, by simulation, values ​​of the variable parameters for reducing bias in communication traffic among each of the plurality of gateways.

6. 3. A ground system for transmitting information indicating a bias in communication traffic among each of said plurality of gateways to the artificial satellite according to claim 1 or 2.

7. An artificial satellite according to claim 1 or 2; A ground system according to claim 6; The plurality of gateways; A satellite communication system comprising:

8. A recording device; A computer, Communication equipment and A satellite communication method performed by a satellite comprising: The communication device includes a beam control device and a beam forming device, the recording device records information indicating communication traffic between the communication device and at least one of a plurality of gateways deployed on the ground; when there is a bias in the communication traffic between each of the plurality of gateways, the computer derives a value of the variable parameter so as to reduce the bias in the communication traffic between each of the plurality of gateways using an inference model that has learned a relationship between the bias in the communication traffic between each of the plurality of gateways and a value of a variable parameter that controls the beam forming device, and transmits information indicating the derived value of the variable parameter to the beam control device; A satellite communication method in which the beam control device receives information indicating values ​​of variable parameters derived by the computer, and controls the beamforming device based on the values ​​of the variable parameters indicated by the received information.

9. An edge server in a terrestrial data center deployed on the ground; A recording device; A computer, Communication equipment and A satellite communication method performed by a satellite comprising: The edge server includes the recording device, The communication device includes a beam control device and a beam forming device, the recording device records information indicating communication traffic between the communication device and at least one of a plurality of gateways deployed on the ground; the computer derives, when there is a bias in communication traffic among each of the plurality of gateways, a value of a variable parameter that controls the beam forming device so as to reduce the bias in communication traffic among each of the plurality of gateways, and transmits information indicating the derived variable parameter value to the beam control device; A satellite communication method in which the beam control device receives information indicating values ​​of variable parameters derived by the computer, and controls the beamforming device based on the values ​​of the variable parameters indicated by the received information.

10. An edge server in a terrestrial data center deployed on the ground; A computer, Communication equipment and An artificial satellite comprising: The communication device includes a beam control device and a beam forming device, The computer is a satellite that derives values ​​of variable parameters that control the beamforming device using an inference model that has learned the relationship between the bias in communication traffic between each of a plurality of gateways deployed on the ground and the values ​​of variable parameters that control the beamforming device.

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