JP2025086737A - Mobile satellite communication system, mobile satellite communication device, mobile satellite communication method, and mobile satellite communication program - Google Patents

Abstract

[Problem] To provide a user terminal location management technique that can improve the efficiency of a satellite mobile communication system. [Solution] The satellite mobile communication system comprises a plurality of non-geostationary satellite devices, each of which comprises a communication means for communicating with terrestrial user terminals and other non-geostationary satellite devices, and a generation means for generating location information that indicates an association between a user terminal connected to the non-geostationary satellite device and a geographical area corresponding to the location of the user terminal, out of a plurality of geographical areas preset on the ground. [Selected Figure] Figure 1

Description

This disclosure relates to a satellite mobile communication system, a satellite mobile communication device, a satellite mobile communication method, and a satellite mobile communication program.

In a typical terrestrial mobile communication system, the location information of a user terminal is managed based on which base station the user terminal is connected to, and communication between user terminals is realized using the location information of the user terminal.

Patent document 1 also describes the creation of a virtual routing area (VRA) in a satellite mobile communication system by developing a graph of associated/connected satellites at any given time interval.

JP 2019-205156 A

In a satellite mobile communication system using a satellite constellation, a non-geostationary satellite that serves as a relay station orbits the Earth once every few hours, and therefore moves much faster than the movement speed of a user terminal. As a result, the relay station to which the user terminal connects is updated, for example, every few minutes to tens of minutes. Therefore, if location information of a user terminal is managed as in the above-mentioned terrestrial mobile communication system, the location information is updated every time the relay station to which the user terminal connects is updated. This results in frequent sending and receiving of management information, which puts strain on the communication bandwidth. Furthermore, if communication is performed at the timing when the relay station is updated, a cache miss may occur in the transfer of communication data.

In addition, the technology described in Patent Document 1 requires cumbersome processing to create a virtual routing area (VRA) at each given time interval.

The present disclosure has been made in consideration of the above problems, and an exemplary objective thereof is to provide a technology for managing the location of user terminals that can improve the efficiency of a satellite mobile communication system.

A satellite mobile communication system device according to an exemplary aspect of the present disclosure includes a plurality of non-geostationary satellite devices, each of which includes a communication means for communicating with a terrestrial user terminal and other non-geostationary satellite devices, and a generation means for generating location information indicating an association between a user terminal connected to the non-geostationary satellite device and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the ground.

A satellite mobile communication device according to an exemplary aspect of the present disclosure is a satellite mobile communication device provided in a non-geostationary satellite device constituting a satellite mobile communication system including a plurality of non-geostationary satellite devices, and includes a communication means for communicating with a terrestrial user terminal and other non-geostationary satellite devices, and a generation means for generating location information indicating an association between a user terminal connected to the satellite mobile communication device and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the ground.

A satellite mobile communication method according to an exemplary aspect of the present disclosure is a satellite mobile communication method using a satellite mobile communication system equipped with multiple non-geostationary satellite devices, in which at least one processor in each non-geostationary satellite device executes a communication process for communicating with a terrestrial user terminal and other non-geostationary satellite devices, and a generation process for generating location information indicating an association between a user terminal connected to the non-geostationary satellite device and a geographical area corresponding to the location of the user terminal among multiple geographical areas preset on the ground.

A satellite mobile communication program according to an exemplary aspect of the present disclosure is a satellite mobile communication program for operating a computer as a satellite mobile communication device provided in a non-geostationary satellite device that constitutes a satellite mobile communication system including multiple non-geostationary satellite devices, and causes the computer to function as a communication means for communicating with a terrestrial user terminal and other non-geostationary satellite devices, and a generation means for generating location information indicating an association between a user terminal connected to the satellite mobile communication device and a geographical area corresponding to the location of the user terminal among multiple geographical areas preset on the ground.

One exemplary aspect of the present disclosure has the exemplary effect of providing a technology for managing the location of user terminals that can improve the efficiency of a satellite mobile communications system.

1 is a block diagram showing a configuration of a satellite mobile communication system according to the present disclosure. 1 is a block diagram showing a configuration of a satellite mobile communication device according to the present disclosure. 1 is a diagram showing an overview of a satellite mobile communication system according to the present disclosure. FIG. 2 is a diagram illustrating an example of the relationship between geographical areas and the coverage area of each non-geostationary satellite device according to the present disclosure. FIG. 1 is a diagram showing a schematic configuration of a non-geostationary satellite device according to the present disclosure. 10 is a flowchart illustrating an example of an operation of a user terminal according to the present disclosure for connecting to a non-geostationary satellite device. 10 is a flowchart illustrating an example of an operation in which user terminals according to the present disclosure communicate with each other. 10 is a flowchart illustrating an example of an operation performed when a connection destination of a user terminal according to the present disclosure is changed. 1 illustrates an example of a user terminal management table according to the present disclosure. 1 illustrates an example of a user area management table according to the present disclosure. 1 illustrates an example of a user area management table according to the present disclosure. 13 illustrates an example of header information according to the present disclosure. 13 illustrates an example of header information according to the present disclosure. 13 illustrates an example of header information according to the present disclosure. 13 illustrates an example of header information according to the present disclosure. 1 illustrates an example of a user terminal management table according to the present disclosure. 5 is a flowchart illustrating an example of a reception processing operation in a non-geostationary satellite device according to the present disclosure. FIG. 2 is a block diagram showing the configuration of a computer that functions as a satellite mobile communication device according to the present disclosure.

The following are examples of embodiments of the present invention. However, the present invention is not limited to the exemplary embodiments shown below, and various modifications are possible within the scope of the claims. For example, embodiments obtained by appropriately combining the technical means employed in the exemplary embodiments shown below may also be included in the scope of the present invention. Furthermore, embodiments obtained by appropriately omitting some of the technical means employed in the exemplary embodiments shown below may also be included in the scope of the present invention. Furthermore, the effects mentioned in the exemplary embodiments shown below are examples of effects expected in the exemplary embodiments, and do not define the scope of the present invention. In other words, embodiments that do not exhibit the effects mentioned in the exemplary embodiments shown below may also be included in the scope of the present invention.

First Exemplary Embodiment
A first exemplary embodiment, which is an example of an embodiment of the present invention, will be described in detail with reference to the drawings. This exemplary embodiment is the basic form of each exemplary embodiment described later. The scope of application of each technical means adopted in this exemplary embodiment is not limited to this exemplary embodiment. That is, each technical means adopted in this exemplary embodiment can be adopted in other exemplary embodiments included in this disclosure to the extent that no particular technical obstacle occurs. In addition, each technical means shown in the drawings referred to for explaining this exemplary embodiment can also be adopted in other exemplary embodiments included in this disclosure to the extent that no particular technical obstacle occurs.

(Configuration of satellite mobile communication system)
The configuration of the satellite mobile communication system 1 will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the configuration of the satellite mobile communication system 1. As shown in Fig. 1, the satellite mobile communication system 1 includes a plurality of non-geostationary satellite devices 10. Each of the plurality of non-geostationary satellite devices 10 functions as a relay station that communicates with a terrestrial user terminal (not shown), and constitutes a so-called satellite constellation.

In this specification, a non-geostationary satellite refers to a satellite that orbits in an orbit other than a geostationary orbit. A non-geostationary satellite generally orbits at a lower altitude than a geostationary orbit, and its position as seen from the ground changes depending on the time of day. In this specification, a satellite constellation refers to a system in which multiple satellites are linked together and operated as a single unit.

Each non-geostationary satellite device 10 is equipped with a communication means 110 for communicating with terrestrial user terminals and other non-geostationary satellite devices 10, and a management means (generation means) 120 for generating and managing location information indicating an association between a user terminal connected to the non-geostationary satellite device 10 and a geographical area corresponding to the location of the user terminal among multiple geographical areas preset on the ground.

In this specification, a geographical region is also referred to as an area, and all terrestrial regions that can be reached while each non-geostationary satellite 10 is orbiting are pre-divided into multiple geographical regions. Note that a certain region can be reached from a non-geostationary satellite 10 means that the non-geostationary satellite 10 can be reached from a user terminal located in that region, and that region is sometimes referred to as the reachable range of the non-geostationary satellite 10. The size of a geographical region is not particularly limited, but may be the same size as the reachable range of a non-geostationary satellite 10. A geographical region is a fixed region, and may be defined, for example, by latitude, longitude, etc.

Furthermore, communication between the non-geostationary satellite device 10 and the user terminal, and communication between the non-geostationary satellite devices 10 may be realized by any technology, for example, communication by radio waves or communication by optical space communication.

(Effects of satellite mobile communication systems)
As described above, in the satellite mobile communication system 1, a configuration is adopted in which each non-geostationary satellite device 10 generates location information indicating the association between a user terminal connected to the non-geostationary satellite device 10 and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the ground.

Since this location information is not based on the relay station to which the user terminal is connected, unlike the terrestrial mobile communication system described above, the location information is not updated every time the relay station to which the user terminal is connected is updated. In addition, the geographical area is fixed, and there is no need to recreate the area at every given time interval, as in the technology described in Patent Document 1. Therefore, according to the satellite mobile communication system 1, it is possible to obtain the effect of providing a technology for managing the location of user terminals that can make the satellite mobile communication system 1 more efficient.

(Configuration of satellite mobile communication device)
The configuration of the satellite mobile communication device 100 will be described with reference to Fig. 2. Fig. 2 is a block diagram showing the configuration of the satellite mobile communication device 100. As shown in Fig. 2, the satellite mobile communication device 100 is provided in a non-geostationary satellite device 10, and realizes the communication function of the non-geostationary satellite device 10. The non-geostationary satellite device 10 is one of a plurality of non-geostationary satellite devices 10 provided in the satellite mobile communication system 1.

The satellite mobile communication device 100 includes a communication means 110 for communicating with terrestrial user terminals and other non-geostationary satellite devices, and a management means (generation means) 120 for generating and managing location information indicating an association between a user terminal connected to the satellite mobile communication device and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the ground.

(Effects of satellite mobile communications devices)
As described above, the satellite mobile communication device 100 employs a configuration for generating location information indicating an association between a user terminal connected to the satellite mobile communication device 100 and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the ground. Therefore, the satellite mobile communication device 100 provides an effect of providing a technology for managing the location of user terminals that can improve the efficiency of the satellite mobile communication system 1 constituted by the non-geostationary satellite device 10 equipped with the satellite mobile communication device 100.

Second Exemplary Embodiment
A second exemplary embodiment, which is an example of an embodiment of the present invention, will be described in detail with reference to the drawings. Components having the same functions as those described in the above exemplary embodiment will be given the same reference numerals, and their description will be omitted as appropriate. The scope of application of each technical means adopted in this exemplary embodiment is not limited to this exemplary embodiment. That is, each technical means adopted in this exemplary embodiment can be adopted in other exemplary embodiments included in this disclosure, as long as no particular technical hindrance occurs. In addition, each technical means shown in each drawing referred to for explaining this exemplary embodiment can be adopted in other exemplary embodiments included in this disclosure, as long as no particular technical hindrance occurs.

Figure 3 is a diagram showing an overview of the satellite mobile communication system 1. In one embodiment, the satellite mobile communication system 1 includes multiple non-geostationary satellite devices 10 that orbit the Earth in the same orbital plane. The number of non-geostationary satellite devices included in the satellite mobile communication system 1 is not particularly limited and can be, for example, 10 to 16, but may be 9 or less, or 17 or more. The orbital planes of the non-geostationary satellite devices 10 included in the satellite mobile communication system 1 do not have to be the same, and the satellite mobile communication system 1 may include multiple non-geostationary satellite devices 10 having different orbital planes. As shown in Figure 3, when each non-geostationary satellite device 10 is to be distinguished, they are referred to as non-geostationary satellite devices S1 to Sn.

In one embodiment, the satellite mobile communication system 1 may include one or more terrestrial base stations BS. The terrestrial base station BS may communicate with any of the non-geostationary satellite devices 10 and may have special functions (e.g., a user authentication function, etc.). The satellite mobile communication system 1 may not include a terrestrial base station BS, and may have the functions of the terrestrial base station BS distributed among the non-geostationary satellite devices 10.

In one aspect, communication between the non-geostationary satellite device 10 and the terrestrial base station BS may be managed by the non-geostationary satellite device 10 that connects to the terrestrial base station BS on a time basis, or the terrestrial base station BS may be managed by geographical area, similar to the user terminal UE, and the non-geostationary satellite device 10 that connects to the terrestrial base station BS may be managed based on the geographical area.

Figure 3 also shows the connection status between the satellite mobile communication system 1 and terrestrial user terminals UE (user terminals UE1 to UE3) and terrestrial base station BS (terrestrial base station BS1) at a certain point in time. At the point in time shown in Figure 3, the non-geostationary satellite device S1 is connected to user terminals UE1 and UE2. Note that the connection destination of the user terminal UE1 switches from the non-geostationary satellite device S1 to the non-geostationary satellite device S2 as each non-geostationary satellite device 10 moves. Also, at the point in time shown in Figure 3, the terrestrial base station BS1 is connected to the non-geostationary satellite device Sn-1, but at a different point in time, the terrestrial base station BS1 may be connected to another non-geostationary satellite device 10.

In addition, various methods can be applied to control the communication paths between non-geostationary satellite devices 10 and between the non-geostationary satellite devices 10 and the terrestrial base station BS, such as time-based path control, dynamic path control such as OSPF, and other path control.

Figure 4 is a diagram showing an example of the relationship between geographical regions (areas) and the connectable range of each non-geostationary satellite device 10. The vertical axis indicates time, with time progressing from the top to the bottom. The horizontal axis indicates the direction of movement of each non-geostationary satellite device 10.

In the example shown in FIG. 4, areas 1 to n are preset as geographical regions. The size of each area is equal to the size of the connectable range of each non-geostationary satellite device 10.

At time t1, the connectivity ranges of the non-geostationary satellite devices S1 to Sn correspond to areas 1 to n, respectively. In other words, the number of geographical areas corresponding to the connectivity range of each non-geostationary satellite device 10 is one. In addition, user terminals UE1 and UE2 located in area 1 are connected to the non-geostationary satellite device S1, and user terminal UE3 located in area 6 is connected to the non-geostationary satellite device S6.

As time progresses to time t2, the connection range of each non-geostationary satellite device 10 spans multiple areas. For example, the connection range of non-geostationary satellite device S1 corresponds to areas 1 and 12. The connection range of non-geostationary satellite device S2 corresponds to areas 1 and 2. At this time, the number of geographical areas corresponding to the connection range of each non-geostationary satellite device 10 is multiple. Also, the number of non-geostationary satellite devices 10 corresponding to one geographical area is also multiple. Also, the connection destination of user terminal UE1 located in area 1 switches to non-geostationary satellite device S2, and the connection destination of user terminal UE2 located in area 1 remains non-geostationary satellite device S1. Also, the connection destination of user terminal UE3 located in area 6 switches to non-geostationary satellite device S7.

As time progresses further, at time t3, the connectable range of each non-geostationary satellite device 10 again coincides with each area. For example, the connectable range of non-geostationary satellite device S1 corresponds to area n. The connectable range of non-geostationary satellite device S2 corresponds to area 1. User terminals UE1 and UE2 located in area 1 are connected to non-geostationary satellite device S2, and user terminal UE3 located in area 6 is connected to non-geostationary satellite device S7.

As described above, the connectivity range of each non-geostationary satellite device 10 may correspond one-to-one with a geographical area at each point in time, the connectivity ranges of multiple non-geostationary satellite devices 10 may correspond to one geographical area, the connectivity range of one non-geostationary satellite device 10 may correspond to multiple geographical areas, or a combination of these. Also, user terminals located in the same area may be connected to the same non-geostationary satellite device 10 or to different non-geostationary satellite devices 10.

Figure 5 is a diagram showing the schematic configuration of a non-geostationary satellite device 10. In this embodiment, the non-geostationary satellite device 10 comprises a satellite mobile communication device 100. The satellite mobile communication device 100 comprises a communication means 110, a user terminal connection management means (generation means, information sharing means) 121, a user communication management means (dispatch means, transfer means) 130, a location information inquiry means (acquisition means) 140, an area address management means (identification means) 150, a user terminal management table T1, a location information management table T2, and an area address management table T3.

The communication means 110 performs communication with the terrestrial user terminal UE, other non-geostationary satellite devices 10, and the terrestrial base station BS. If the satellite mobile communication system 1 does not have a terrestrial base station BS, the communication means 110 performs communication with the terrestrial user terminal UE and other non-geostationary satellite devices 10. The communication means 110 may perform communication with the user terminal UE, other non-geostationary satellite devices 10, and the terrestrial base station BS using the same communication method or different communication methods. Also, the communication means 110 for performing communication with the user terminal UE, the communication means 110 for performing communication with other non-geostationary satellite devices 10, and the communication means 110 for performing communication with the terrestrial base station BS may be provided separately.

The user terminal connection management means 121 processes connection requests from the user terminal UE. For example, in one embodiment, if the terrestrial base station BS has a user authentication function, the user terminal connection management means 121 transmits a connection request from the user terminal UE to the terrestrial base station BS via another non-geostationary satellite device 10, and transmits a response from the terrestrial base station BS to the user terminal UE.

The user terminal connection management means 121 also generates and manages location information indicating the association between a user terminal UE connected to the non-geostationary satellite device 10 and a geographical area corresponding to the location of the user terminal among multiple geographical areas preset on the ground.

In detail, the connection request from the user terminal UE includes location information of the user terminal UE. Based on the connection information, the user terminal connection management means 121 generates location information indicating an association between the user terminal UE attempting to connect to the non-geostationary satellite device 10 and the geographical area corresponding to the location of the user terminal UE, and transmits the location information together with the connection request to the terrestrial base station BS. Note that the location information may be associated with identification information indicating the non-geostationary satellite device 10. The user terminal connection management means 121 may also store the generated location information in the user terminal management table T1.

If the response from the terrestrial base station BS is permission to connect the user terminal UE, the user terminal connection management means 121 may transmit the location information of the user terminal UE connected to the non-geostationary satellite device 10 stored in the user terminal management table T1 to the other non-geostationary satellite device 10. In particular, the user terminal connection management means 121 may transmit the location information of the user terminal UE connected to the non-geostationary satellite device 10 to a nearby non-geostationary satellite device 10. The other non-geostationary satellite device 10 that receives the location information of the user terminal UE stores the received location information in the location information management table T2 of the other non-geostationary satellite device 10. At this time, the location information of the user terminal UE stored in the location information management table T2 may be associated with identification information indicating the non-geostationary satellite device 10 to which the user terminal UE is connected.

In one aspect, the user terminal connection management means 121 may transmit location information of the user terminal UE connected to the non-geostationary satellite device 10 to at least one of the first nearby non-geostationary satellite device and the second nearby non-geostationary satellite device. The first nearby non-geostationary satellite device is a non-geostationary satellite device whose connectable range includes the geographical area indicated by the location information. The second nearby non-geostationary satellite device is a non-geostationary satellite device whose connectable range next includes the geographical area indicated by the location information. Note that "the geographical area is next included in the connectable range" means that the geographical area is located adjacent to the connectable range of the non-geostationary satellite device in the movement direction of the non-geostationary satellite device, and is included in the connectable range of the non-geostationary satellite device by moving in the orbital plane.

In this way, by transmitting location information of a user terminal UE connected to a non-geostationary satellite device 10 to other non-geostationary satellite devices 10, particularly to nearby non-geostationary satellite devices 10, the location information of the user terminal UE can be shared with the other non-geostationary satellite devices 10, and processing can be smoothly carried out when the user terminal UE connects to another non-geostationary satellite device 10.

In particular, since the first nearby non-geostationary satellite device 10 and the second nearby non-geostationary satellite device 10 are likely to be connected to by a user terminal UE, it is beneficial to share the location information of the user terminal UE. In one embodiment, as described below, in the satellite mobile communication system 1, communication content addressed to a certain user terminal UE is transmitted to the non-geostationary satellite device 10 corresponding to the geographical area of the user terminal UE based on the geographical area of the user terminal UE. At this time, even if there are multiple non-geostationary satellite devices 10 corresponding to the geographical area, if the location information of the user terminal UE connected to the nearby non-geostationary satellite device 10 is shared, the communication content can be transmitted quickly to the target user terminal UE.

In the above, the case where each non-geostationary satellite device 10 has the same orbital plane has been described, but as mentioned above, the satellite mobile communication system 1 may also include multiple non-geostationary satellite devices 10 having different orbital planes. In this case, location information may be shared with non-geostationary satellite devices 10 having the same orbital plane as nearby non-geostationary satellite devices 10. However, considering that the position of the non-geostationary satellite devices 10 as seen from the ground shifts due to the rotation of the Earth, location information may also be shared with non-geostationary satellite devices 10 having different orbital planes as nearby non-geostationary satellite devices 10.

The user terminal connection management means 121 may also transmit, in addition to the location information, information indicating the scheduled time when the geographical area corresponding to the connectable range of the non-geostationary satellite device 10 will change to the other non-geostationary satellite device 10. This makes it possible to more smoothly proceed with the process when the geographical area corresponding to the connectable range of the non-geostationary satellite device 10 changes and the connection destination of the user terminal UE connected to the non-geostationary satellite device 10 is switched to another non-geostationary satellite device 10.

The user communication management means 130 manages the communications of the user terminal UE connected to the non-geostationary satellite device 10.

In one aspect, when a non-geostationary satellite device 10 receives communication content addressed to a specific user terminal UE from a user terminal UE connected to the non-geostationary satellite device 10, the user communication management means 130 transmits the communication content addressed to the specific user terminal UE to another non-geostationary satellite device 10 in association with information identifying the geographical area corresponding to the location of the specific user terminal UE.

The information identifying the geographical area is not particularly limited as long as it is information capable of identifying the geographical area, but may be, for example, an address corresponding to the geographical area.

The location information management table T2 stores location information indicating an association between a user terminal UE connected to another non-geostationary satellite device 10 and the geographical area in which the user terminal UE is located, and the user communication management means 130 may refer to the location information management table T2 to obtain information identifying the geographical area corresponding to the location of a specific user terminal UE.

In addition, if the location information management table T2 does not include location information for a specific user terminal UE, the location information inquiry means 140 may inquire about the location information for the specific user terminal UE and obtain the location information for the specific user terminal UE.

In detail, first, the satellite mobile communication system 1 further includes a collection means for collecting location information managed by the user terminal connection management means 121 of each non-geostationary satellite device 10. In one embodiment, the terrestrial base station BS functions as the collection means. Then, the location information inquiry means 140 may obtain the location information of a specific user terminal UE directly from the terrestrial base station BS, or from the terrestrial base station BS via another non-geostationary satellite device 10.

This allows the user communication management means 130 to transmit communication content addressed to a specific user terminal UE to another non-geostationary satellite device 10 in association with information identifying the geographical area corresponding to the location of the specific user terminal UE.

In addition, when a non-geostationary satellite device 10 receives communication content associated with identification information identifying a geographical area from another non-geostationary satellite device 10, the user communication management means 130 compares the geographical area indicated by the identification information with the geographical area corresponding to the connectable range of the non-geostationary satellite device 10, and if they do not match, transfers the communication content to a non-geostationary satellite device 10 other than the other non-geostationary satellite device 10, and if they match, transmits the communication content to the destination user terminal UE.

The geographical area corresponding to the connectable range of the non-geostationary satellite device 10 is identified, for example, by the area address management means 150. In one embodiment, the area address management means 150 refers to an area address management table T3 indicating the correspondence between the position of the non-geostationary satellite device 10 and an address indicating a geographical area, and automatically updates the address indicating the geographical area corresponding to the connectable range of the non-geostationary satellite device 10 based on the position of the non-geostationary satellite device 10.

In one aspect, the area address management table T3 may be a table showing the correspondence between the position of the non-geostationary satellite device 10 and an address that identifies a geographical area, or may show parameters for calculations to identify an address that indicates a geographical area from the position of the non-geostationary satellite device 10.

This allows the user communication management means 130 to appropriately process the communication contents received from other non-geostationary satellite devices 10. If the communication contents received from other non-geostationary satellite devices 10 include information on the sending user terminal UE and information indicating the geographical area of the sending user terminal UE, the user communication management means 130 may generate location information of the sending user terminal UE based on these and store it in the location information management table T2.

The area address management means 150 may also obtain the location of nearby non-geostationary satellite devices 10 and automatically update the addresses indicating the geographical areas corresponding to the connectivity ranges of the nearby non-geostationary satellite devices 10.

Next, the operation of the satellite mobile communication system 1 will be described with reference to Figures 6 to 8. Figures 6 to 8 are flowcharts showing an example of the operation of the satellite mobile communication system 1.

First, referring to FIG. 6, we will explain the operation of user terminals UE1 and UE3 connecting to non-geostationary satellite devices S1 and S6, respectively.

In step S100, the non-geostationary satellite device S1 transmits a reference signal within the connectable range (reference burst). In step S102, the user terminal UE1, which has received the reference signal from the non-geostationary satellite device S1, transmits a connection request to the non-geostationary satellite device S1. At this time, the connection request includes location information of the user terminal UE1.

In step S104, the user terminal connection management means 121 of the non-geostationary satellite device S1 generates location information for the user terminal UE1 based on the connection request and stores it in the user terminal management table T1. Figure 9 shows an example of the user terminal management table T1 in step S104.

In steps S106 to S108, the user terminal connection management means 121 of the non-geostationary satellite device S1 transmits a connection request and location information of the user terminal UE1 to the terrestrial base station BS1 via the relay station (non-geostationary satellite device Sn).

In step S110, the terrestrial base station BS1 authenticates the connection of the user terminal UE1 based on the connection request of the user terminal UE1, and adds the location information of the user terminal UE1 to the user area management table of the terrestrial base station BS1. FIG. 10 shows an example of the user area management table in step S110.

Then, in steps S112 to S114, the terrestrial base station BS1 transmits the authentication result of the connection of the user terminal UE1 to the non-geostationary satellite device S1 via the relay station (non-geostationary satellite device Sn).

In step S116, the user terminal connection management means 121 of the non-geostationary satellite device S1 transmits the authentication result of the connection of the user terminal UE1 to the user terminal UE1. In addition, in step S118, the user terminal connection management means 121 transmits the location information stored in the user terminal management table T1 to the nearby non-geostationary satellite device S2. As a result, the location information as shown in FIG. 9 is also stored in the user terminal management table T1 of the non-geostationary satellite device S2.

In addition, in step S120, the non-geostationary satellite device S6 transmits a reference signal within the connectable range (reference burst). In step S122, the user terminal UE3 that has received the reference signal from the non-geostationary satellite device S6 transmits a connection request to the non-geostationary satellite device S6. At this time, the connection request includes location information of the user terminal UE3.

In step S124, the user terminal connection management means 121 of the non-geostationary satellite device S6 generates location information for the user terminal UE3 based on the connection request and stores it in the user terminal management table T1.

In steps S126 to S130, the user terminal connection management means 121 of the non-geostationary satellite device S6 transmits a connection request and location information of the user terminal UE3 to the terrestrial base station BS1 via the relay station.

In step S132, the terrestrial base station BS1 authenticates the connection of the user terminal UE3 based on the connection request of the user terminal UE3, and adds the location information of the user terminal UE3 to the user area management table of the terrestrial base station BS1. FIG. 11 shows an example of the user area management table in step S132.

Then, in steps S134 to S138, the terrestrial base station BS1 transmits the authentication result of the connection of the user terminal UE3 to the non-geostationary satellite device S6 via the relay station.

In step S140, the user terminal connection management means 121 of the non-geostationary satellite device S6 transmits the authentication result of the connection of the user terminal UE3 to the user terminal UE3. In addition, in step S142, the user terminal connection management means 121 transmits the location information stored in the user terminal management table T1 to a nearby non-geostationary satellite device (not shown).

Next, referring to Figure 7, we will explain the operation of user terminals UE1 and UE3 communicating with each other.

In step S200, the user terminal UE3 transmits the communication content addressed to the user terminal UE1 to the non-geostationary satellite device S6. FIG. 12 shows an example of the header information of the communication content addressed to the user terminal UE1.

In steps S202 to S206, the location information inquiry means 140 of the non-geostationary satellite device S6 makes an inquiry to the terrestrial base station BS1 about the location information of the user terminal UE1 via the relay station.

In step S208, the terrestrial base station BS1 refers to a user area management table such as that shown in FIG. 11 to identify the location information of the user terminal UE1. Then, in steps S210 to S214, the terrestrial base station BS1 transmits the location information of the user terminal UE1 to the non-geostationary satellite device S6 via the relay station.

Then, in S216, the user communication management means 130 of the non-geostationary satellite device S6 encapsulates the communication content addressed to the user terminal UE1 based on the location information of the user terminal UE1, associating it with information identifying the geographical area corresponding to the location of the user terminal UE1 (address of area 1), and transmits it to the non-geostationary satellite device S1 via the relay station. Figure 13 shows an example of the header information of the encapsulated communication content.

In step S218, the user communication management means 130 of the non-geostationary satellite device S1 decapsulates the communication content addressed to the user terminal UE1 and transmits it to the user terminal UE1.

In addition, in step S220, the user terminal UE1 transmits the communication content addressed to the user terminal UE3 to the non-geostationary satellite device S1. FIG. 14 shows an example of the header information of the communication content addressed to the user terminal UE3.

In steps S222 to S224, the location information inquiry means 140 of the non-geostationary satellite device S1 makes an inquiry to the terrestrial base station BS1 via the relay station about the location information of the user terminal UE3.

In step S226, the terrestrial base station BS1 refers to a user area management table such as that shown in FIG. 11 to identify the location information of the user terminal UE3. Then, in steps S228 to S230, the terrestrial base station BS1 transmits the location information of the user terminal UE3 to the non-geostationary satellite device S1 via the relay station.

Then, in S232, the user communication management means 130 of the non-geostationary satellite device S1 encapsulates the communication content addressed to the user terminal UE3 based on the location information of the user terminal UE3, associating it with information identifying the geographical area corresponding to the location of the user terminal UE3 (address of area 6), and transmits it to the non-geostationary satellite device S6 via the relay station. Figure 15 shows an example of the header information of the encapsulated communication content.

In step S234, the user communication management means 130 of the non-geostationary satellite device S6 decapsulates the communication content addressed to the user terminal UE3 and transmits it to the user terminal UE3.

Next, referring to Figure 8, we will explain the operation when the connection destination of user terminal UE1 is changed.

In step S300, the non-geostationary satellite device S2 transmits a reference signal within the connectable range (reference burst). In step S302, the user terminal UE1, which has received the reference signal from the non-geostationary satellite device S2, transmits a connection request to the non-geostationary satellite device S2. This changes the connection destination of the user terminal UE1 from the non-geostationary satellite device S1 to the non-geostationary satellite device S2.

In step S304, the user terminal connection management means 121 of the non-geostationary satellite device S2 updates the location information in the user terminal management table T1 and transmits the updated location information to the nearby non-geostationary satellite devices S1 and S3. Note that the non-geostationary satellite device S1 is the first nearby non-geostationary satellite device described above, and the non-geostationary satellite device S3 is the second nearby non-geostationary satellite device described above. FIG. 16 shows an example of the updated location information.

In step S306, the user terminal UE3 transmits the communication content addressed to the user terminal UE1 to the non-geostationary satellite device S6.

In step S308, the user communication management means 130 of the non-geostationary satellite device S6 encapsulates and transmits the communication content addressed to the user terminal UE1 in association with information identifying the geographical area corresponding to the location of the user terminal UE1 (address of area 1), and assumes that the communication content has arrived at the non-geostationary satellite device S3. In this case, since the location information stored in the user terminal management table T1 of the non-geostationary satellite device S3 indicates that the user terminal UE1 is connected to the non-geostationary satellite device S2, in step S310, the user communication management means 130 of the non-geostationary satellite device S3 transmits the communication content addressed to the user terminal UE1 to the non-geostationary satellite device S2. Then, in step S312, the user communication management means 130 of the non-geostationary satellite device S2 transmits the communication content addressed to the user terminal UE1 to the user terminal UE1.

In addition, in step S314, the user communication management means 130 of the non-geostationary satellite device S6 encapsulates and transmits the communication content addressed to the user terminal UE1 in association with information identifying the geographical area corresponding to the location of the user terminal UE1 (address of area 1), and assumes that the communication content has reached the non-geostationary satellite device S1. In this case, since the location information stored in the user terminal management table T1 of the non-geostationary satellite device S1 indicates that the user terminal UE1 is connected to the non-geostationary satellite device S2, in step S318, the user communication management means 130 of the non-geostationary satellite device S1 transmits the communication content addressed to the user terminal UE1 to the non-geostationary satellite device S2. Then, in step S320, the user communication management means 130 of the non-geostationary satellite device S2 transmits the communication content addressed to the user terminal UE1 to the user terminal UE1.

Figure 17 is a flowchart showing an example of the operation of reception processing in a non-geostationary satellite device 10.

In step S400, the non-geostationary satellite device 10 receives communication content from another non-geostationary satellite device 10. The header information of the communication content indicates the destination geographic area, for example, as shown in FIG. 13.

In step S402, the user communication management means 130 of the non-geostationary satellite device 10 determines whether the address indicating the destination geographical area contained in the header information matches the address indicating the geographical area to which the connectable range of the non-geostationary satellite device 10 identified by the area address management means 150 corresponds.

If there is no match in step S402, in step S404, the user communication management means 130 transfers the communication content to another non-geostationary satellite device 10.

If there is a match in step S402, in step S406, the user communication management means 130 refers to the user terminal management table T1 to determine whether the user terminal UE indicated by the header information is a user terminal UE connected to the non-geostationary satellite device 10.

If in step S406 the user terminal UE is not connected to the non-geostationary satellite device 10, in step S408 the user communication management means 130 refers to the location information management table T2 and transfers the communication content to the non-geostationary satellite device 10 to which the user terminal UE is connected.

If, in step S406, the user terminal UE is connected to the non-geostationary satellite device 10, in step S410, the user communication management means 130 decapsulates the communication contents and transfers the communication contents to the user terminal UE.

In addition, in step S408, the user communication management means 130 may change the address indicating the destination geographical area in the header information to an address identifying the non-geostationary satellite device 10 to which the user terminal UE is connected, and transfer the communication content to the non-geostationary satellite device 10. This can reduce the processing in the non-geostationary satellite device 10 to which the communication content is to be transferred.

In the above, the location information of the user terminal UE is determined by the position of the user terminal UE, but this is not necessarily the case. For example, if there is a non-geostationary satellite device S1 corresponding to area 1 and a non-geostationary satellite device S2 corresponding to area 2, and a user terminal UE1 located in area 1 is connected to the non-geostationary satellite device S2, area 2 may be associated as the location information of the user terminal UE1.

In addition, the procedure for the user terminal UE to change the connection destination is not particularly limited. In the example shown in FIG. 8, when the user terminal UE1 changes the connection destination from the non-geostationary satellite device S1 to the non-geostationary satellite device S2, the user terminal UE1 that has received the reference burst of the non-geostationary satellite device S2 makes a connection request to the non-geostationary satellite device S2, but this is not limited to this. For example, the user terminal UE1 that has received the reference burst of the non-geostationary satellite device S2 may transmit receivable satellite information to the non-geostationary satellite device S1 and switch the connection destination based on a handover instruction from the non-geostationary satellite device S1. In addition, after the user terminal UE1 that has received the reference burst of the non-geostationary satellite device S2 makes a connection request to the non-geostationary satellite device S2, a handover request is made from the non-geostationary satellite device S2 to the non-geostationary satellite device S1, and the user terminal UE1 may switch the connection destination based on a handover instruction from the non-geostationary satellite device S1.

According to the inventors' simulations, by applying the present disclosure, it is possible to obtain effects such as, for example, the number of communications and communication bandwidth for managing location information between a non-geostationary satellite device 10 and a terrestrial base station BS, the number of communications and communication bandwidth for sharing location information between neighboring non-geostationary satellite devices 10, and reduction in cache misses and resulting delays in communications using location information.

[Software implementation example]
Some or all of the functions of the non-geostationary satellite device 10 and the satellite mobile communication device 100 (hereinafter also referred to as "the above-mentioned devices") may be realized by hardware such as an integrated circuit (IC chip), or by software.

In the latter case, each of the above devices is realized, for example, by a computer that executes instructions of a program, which is software that realizes each function. An example of such a computer (hereinafter referred to as computer C) is shown in FIG. 18. FIG. 18 is a block diagram showing the hardware configuration of computer C that functions as each of the above devices.

Computer C has at least one processor C1 and at least one memory C2. Memory C2 stores a program P for operating computer C as each of the above devices. In computer C, processor C1 reads and executes program P from memory C2, thereby realizing each function of each of the above devices.

The processor C1 may be, for example, a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), a DSP (Digital Signal Processor), an MPU (Micro Processing Unit), an FPU (Floating point number Processing Unit), a PPU (Physics Processing Unit), a TPU (Tensor Processing Unit), a quantum processor, a microcontroller, or a combination of these. The memory C2 may be, for example, a flash memory, an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination of these.

The computer C may further include a RAM (Random Access Memory) for expanding the program P during execution and for temporarily storing various data. The computer C may further include a communication interface for transmitting and receiving data to and from other devices. The computer C may further include an input/output interface for connecting input/output devices such as a keyboard, mouse, display, and printer.

The program P can also be recorded on a non-transitory, tangible recording medium M that can be read by the computer C. Such a recording medium M can be, for example, a tape, a disk, a card, a semiconductor memory, or a programmable logic circuit. The computer C can obtain the program P via such a recording medium M. The program P can also be transmitted via a transmission medium. Such a transmission medium can be, for example, a communications network or broadcast waves. The computer C can also obtain the program P via such a transmission medium.

[Additional Note 1]
This disclosure includes the techniques described in the following appendices. However, the present invention is not limited to the techniques described in the following appendices, and various modifications are possible within the scope of the claims.

(Appendix 1)
A satellite mobile communication system comprising a plurality of non-geostationary satellite devices, each of which comprises a communication means for communicating with a terrestrial user terminal and other non-geostationary satellite devices, and a generation means for generating location information indicating an association between a user terminal connected to the non-geostationary satellite device and one of a plurality of geographical areas preset on the ground that corresponds to the location of the user terminal.

(Appendix 2)
2. The satellite mobile communications system of claim 1, wherein each non-geostationary satellite device further comprises an identification means for identifying one or more of the geographical areas corresponding to the connectivity range of the non-geostationary satellite device.

(Appendix 3)
A satellite mobile communication system as described in Appendix 2, wherein each non-geostationary satellite device receives communication content associated with identification information identifying a geographical area from other non-geostationary satellite devices, and if the geographical area indicated by the identification information is compared and does not match the geographical area identified by the identification means, transfers the communication content to a non-geostationary satellite device other than the other non-geostationary satellite devices.

(Appendix 4)
A satellite mobile communications system as described in Appendix 1, wherein each non-geostationary satellite device further comprises a forwarding means for transmitting communication content addressed to a particular user terminal to other non-geostationary satellite devices in association with information identifying the geographical area corresponding to the location of the particular user terminal.

(Appendix 5)
A satellite mobile communications system as described in Appendix 4, further comprising a collection means for collecting the location information generated by the generation means of each non-geostationary satellite device, and each non-geostationary satellite device further comprising an acquisition means for acquiring the geographical area corresponding to the location of the particular user terminal from the collection means.

(Appendix 6)
2. The satellite mobile communications system of claim 1, wherein each non-geostationary satellite device further comprises an information sharing means for transmitting the location information to other non-geostationary satellite devices.

(Appendix 7)
The satellite mobile communication system described in Appendix 6, wherein the information sharing means transmits the location information to at least one of a first nearby non-geostationary satellite device and a second nearby non-geostationary satellite device among the plurality of non-geostationary satellite devices, the first nearby non-geostationary satellite device being a non-geostationary satellite device whose connectable range includes the geographical area indicated by the location information, and the second nearby non-geostationary satellite device being a non-geostationary satellite device whose connectable range next includes the geographical area indicated by the location information.

(Appendix 8)
A satellite mobile communication device provided in a non-geostationary satellite device that constitutes a satellite mobile communication system having a plurality of non-geostationary satellite devices, the satellite mobile communication device comprising: a communication means for communicating with a terrestrial user terminal and other non-geostationary satellite devices; and a generation means for generating location information indicating an association between a user terminal connected to the satellite mobile communication device and one of a plurality of geographical areas preset on the ground that corresponds to the location of the user terminal.

(Appendix 9)
A satellite mobile communication method using a satellite mobile communication system having a plurality of non-geostationary satellite devices, in which at least one processor provided in each non-geostationary satellite device performs a communication process for communicating with a terrestrial user terminal and other non-geostationary satellite devices, and a generation process for generating location information indicating an association between a user terminal connected to the non-geostationary satellite device and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the ground.

(Appendix 10)
A satellite mobile communications program for operating a computer as a satellite mobile communications device provided in a non-geostationary satellite device that constitutes a satellite mobile communications system having a plurality of non-geostationary satellite devices, the program causing the computer to function as a communication means for communicating with terrestrial user terminals and other non-geostationary satellite devices, and a generation means for generating location information indicating an association between a user terminal connected to the satellite mobile communications device and one of a plurality of geographical areas preset on the ground that corresponds to the location of the user terminal.

[Additional Note 2]
This disclosure includes the techniques described in the following appendices. However, the present invention is not limited to the techniques described in the following appendices, and various modifications are possible within the scope of the claims.

(Appendix 1)
A satellite mobile communication system comprising a plurality of non-geostationary satellite devices, each of which has at least one processor, and which executes a communication process for communicating with a terrestrial user terminal and other non-geostationary satellite devices, and a generation process for generating location information indicating an association between a user terminal connected to the non-geostationary satellite device and a geographical area corresponding to the location of the user terminal, among a plurality of geographical areas preset on the ground.

The non-geostationary satellite device may further include a memory. The memory may also store a program for causing the at least one processor to execute each of the processes.

(Appendix 2)
A satellite mobile communication device provided in a non-geostationary satellite device that constitutes a satellite mobile communication system having a plurality of non-geostationary satellite devices, the satellite mobile communication device having at least one processor, the at least one processor performing a communication process for communicating with a terrestrial user terminal and other non-geostationary satellite devices, and a generation process for generating location information indicating an association between a user terminal connected to the satellite mobile communication device and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the ground.

The non-geostationary satellite device may further include a memory. The memory may also store a program for causing the at least one processor to execute each of the processes.

1 Satellite mobile communication system 10, S1 to Sn Non-geostationary satellite device 100 Satellite mobile communication device 110 Communication means 120 Management means 121 User terminal connection management means 130 User communication management means 140 Location information inquiry means 150 Area address management means T1 User terminal management table T2 Location information management table T3 Area address management table

Claims (10)

A plurality of non-geostationary satellite devices are provided,
Each non-geostationary satellite device:
communication means for communicating with terrestrial user terminals and other non-geostationary satellite devices;
A satellite mobile communication system comprising: a generating means for generating location information indicating an association between a user terminal connected to the non-geostationary satellite device and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the earth. Each non-geostationary satellite device:
2. The satellite mobile communications system according to claim 1, further comprising identifying means for identifying one or more of said geographical areas corresponding to coverage areas of said non-geostationary satellite units. Each non-geostationary satellite device:
3. The satellite mobile communication system according to claim 2, further comprising a transfer means for receiving communication content associated with identification information identifying a geographical area from another non-geostationary satellite device, and transferring the communication content to a non-geostationary satellite device other than the other non-geostationary satellite device if the geographical area indicated by the identification information is not identical to the geographical area identified by the identification means. Each non-geostationary satellite device:
2. The satellite mobile communications system of claim 1, further comprising a forwarding means for transmitting communications addressed to a particular user terminal to other non-geostationary satellite devices in association with information identifying the geographic area corresponding to the location of the particular user terminal. a collection means for collecting the location information generated by the generation means of each non-geostationary satellite device;
Each non-geostationary satellite device:
5. The satellite mobile communications system of claim 4, further comprising: obtaining means for obtaining from said collecting means said geographic area corresponding to the location of said particular user terminal. Each non-geostationary satellite device:
2. The satellite mobile communications system according to claim 1, further comprising information sharing means for transmitting said location information to other non-geostationary satellite devices. the information sharing means transmits the location information to at least one of a first nearby non-geostationary satellite device and a second nearby non-geostationary satellite device among the plurality of non-geostationary satellite devices;
the first nearby non-geostationary satellite device is a non-geostationary satellite device having a connectable range that includes the geographical area indicated by the location information;
7. The satellite mobile communications system according to claim 6, wherein the second nearby non-geostationary satellite device is a non-geostationary satellite device whose connectable range next includes the geographical area indicated by the location information. A satellite mobile communication device provided in a non-geostationary satellite device constituting a satellite mobile communication system having a plurality of non-geostationary satellite devices,
communication means for communicating with terrestrial user terminals and other non-geostationary satellite devices;
A satellite mobile communication device comprising: a generating means for generating location information indicating an association between a user terminal connected to the satellite mobile communication device and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the earth. A satellite mobile communication method for a satellite mobile communication system having a plurality of non-geostationary satellite devices, comprising:
At least one processor included in each non-geostationary satellite device,
a communications process for communicating with terrestrial user terminals and other non-geostationary satellite devices;
A satellite mobile communication method which executes a generation process for generating location information indicating an association between a user terminal connected to the non-geostationary satellite device and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the ground. A satellite mobile communication program for operating a computer as a satellite mobile communication device provided in a non-geostationary satellite device constituting a satellite mobile communication system having a plurality of non-geostationary satellite devices, comprising:
A satellite mobile communications program that causes the computer to function as a communications means for communicating with terrestrial user terminals and other non-geostationary satellite devices, and a generating means for generating location information indicating an association between a user terminal connected to the satellite mobile communications device and a geographical area corresponding to the location of the user terminal among a plurality of geographical areas preset on the ground.

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