Transition of communication device to connection state in accordance with operation schedule of base station

Abstract

To provide a communication control apparatus and a communication control method that alleviate concentration of signal processing load caused by changes in an operation state of a base station.SOLUTION: In a wireless communication system, a communication control apparatus 3 comprises at least one processor that executes: acquiring an operation schedule of a base station by an operation schedule acquisition unit; identifying a communication device that may transition to a non-connectable state with the base station by a communication device identification unit; and transitioning, by a connection control unit, the communication device from a connection standby state to a connection state with the base station and / or another base station before the communication device transitions to the non-connectable state. The base station is a mobile base station that moves relative to the communication device. In the base station, the operation schedule acquisition unit acquires a movement schedule of the mobile base station, the communication device identification unit identifies a communication device that may become outside a mobile communication cell provided by the mobile base station, and the connection control unit transitions the communication device from the connection standby state to a connection state with the mobile base station and / or another base station before the communication device becomes outside the mobile communication cell.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to transitions to connection states of communication devices in accordance with base station operation schedules. [Background technology]

[0002] The number, types, and uses of wireless communication devices, such as smartphones and Internet of Things (IoT) devices, are steadily increasing, and wireless communication standards are continually being expanded and improved. For example, commercial service for the fifth-generation mobile communication system, known as "5G," began in 2018, and standardization is still underway at the Third Generation Partnership Project (3GPP). In addition, efforts have begun to develop standards for the sixth-generation mobile communication system, or "6G," as the next-generation wireless communication standard following 5G.

[0003] Mobile communication (hereinafter also referred to as mobile communication) networks for mobile or portable communication devices (hereinafter collectively referred to as communication devices), such as smartphones and mobile phones, have generally been constructed using communication cells (hereinafter also referred to as terrestrial communication cells) provided by base stations (hereinafter also referred to as terrestrial base stations) installed on the ground. However, in some areas, it is difficult to install a sufficient number of terrestrial base stations for various reasons, which has led to the problem of relatively low quality of mobile communication.

[0004] To address these regional disparities in mobile communication quality and the "out-of-area" problem of mobile communication devices being unable to communicate in some areas, non-terrestrial networks (NTNs) are being considered. In NTNs, communication satellites and unmanned aerial vehicles flying in the atmosphere, such as outer space and the stratosphere, serve as base stations (hereinafter referred to as non-terrestrial base stations, and communication satellites in particular are also referred to as satellite base stations) and provide communication cells on the ground (hereinafter referred to as non-terrestrial communication cells, and communication cells provided by communication satellites in particular are also referred to as satellite communication cells). Devices within non-terrestrial communication cells communicate with non-terrestrial base stations directly or indirectly via other communication devices. Providing non-terrestrial communication cells in areas where terrestrial communication cells are insufficient can improve the quality of mobile communication in those areas. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-278886 Summary of the Invention [Problem to be solved by the invention]

[0006] When a mobile base station, such as a communications satellite, moves relative to a communication device, the communication device may transition from being within the range of the mobile base station to being out of range. When a large number of communication devices suddenly become out of range, they simultaneously search for and attempt to connect to other available base stations, resulting in a concentrated increase in the signal processing load on the network. A similar situation can occur, for example, when a base station with limited operating time transitions from an operating state to a stopped state.

[0007] The present disclosure has been made in view of these circumstances, and aims to provide a communication control device and the like that can alleviate the concentration of signal processing load caused by changes in the operating status of base stations. [Means for solving the problem]

[0008] In order to solve the above problem, a communication control device of one aspect of the present disclosure includes at least one processor that performs the following operations: acquiring an operation schedule of a base station using an operation schedule acquisition unit; identifying a communication device that is in a connection standby state with a base station and that may transition to a connection unavailable state with the base station according to the operation schedule using a communication device identification unit; and transitioning the communication device from the connection standby state to a connection state with the base station and / or other base stations using a connection control unit before transitioning to the connection unavailable state.

[0009] In this mode, a communication device that is in a connection standby state (hereinafter also referred to as an idle state) with a base station is transitioned from the connection standby state to a connection state before transitioning to a state in which connection with the base station is unavailable. In this way, the communication device can start searching for other base stations before going "out of range" (connection unavailable state), thereby mitigating the concentration of signal processing load on the network side.

[0010] Another aspect of the present disclosure is a communication control method, which includes: acquiring an operation schedule of a base station; identifying a communication device that is in a connection standby state with the base station and that may transition to a connection unavailable state with the base station according to the operation schedule; and transitioning the communication device from the connection standby state to a connection state with the base station and / or another base station before transitioning to the connection unavailable state.

[0011] Yet another aspect of the present disclosure is a storage medium that stores a communication control program that causes a computer to acquire an operation schedule of a base station, identify a communication device that is in a connection standby state with the base station and that may transition to a connection-disabled state with the base station according to the operation schedule, and transition the communication device from the connection standby state to a connection state with the base station and / or another base station before transitioning to the connection-disabled state.

[0012] Any combination of the above components, or any conversion of these expressions into methods, devices, systems, recording media, computer programs, etc., are also encompassed within the present disclosure. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to alleviate the concentration of signal processing load caused by changes in the operating status of base stations. [Brief explanation of the drawings]

[0014] [Figure 1] 1 shows a schematic overview of a wireless communication system to which a communication control device is applied. [Figure 2] 2 shows a schematic diagram of an example of a location registration area configured by a terrestrial communication cell and a non-terrestrial communication cell. [Figure 3] FIG. 2 is a functional block diagram of a communication control device. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1 schematically illustrates an overview of a wireless communication system 1 to which a communication control device according to an embodiment of the present disclosure is applied. The wireless communication system 1 includes a 5G wireless communication system 11 conforming to a fifth-generation mobile communication system (5G) that uses NR (New Radio) or 5G NR (Fifth Generation New Radio) as a radio access technology (RAT) and 5GC (Fifth Generation Core) as a core network (CN), a 4G wireless communication system 12 conforming to a fourth-generation mobile communication system (4G) that uses LTE (Long Term Evolution) or LTE-Advanced as a radio access technology and EPC (Evolved Packet Core) as a core network, and a satellite communication system 13 that performs satellite communication via a communication satellite 131. Although not illustrated, the wireless communication system 1 may include a wireless communication system of a generation earlier than 4G, a wireless communication system of a generation later than 5G (e.g., 6G), or any wireless communication system not associated with a generation, such as Wi-Fi (registered trademark).

[0016] The 5G wireless communication system 11 includes communication devices 2A, 2B, 2C, and 2D (hereinafter sometimes collectively referred to as communication devices 2) such as smartphones that are installed on the ground and are also called UE (User Equipment), and multiple 5G base stations 111A, 111B, and 111C (hereinafter sometimes collectively referred to as 5G base stations 111) that can communicate via 5G NR. In 5G, the base station 111 is also called a gNodeB (gNB). The communication range or support area of ​​each of the 5G base stations 111A, 111B, and 111C is called a cell, and is illustrated as 112A, 112B, and 112C, respectively (hereinafter sometimes collectively referred to as 5G cells 112).

[0017] The size of the 5G cell 112 of each 5G base station 111 is arbitrary, but typically ranges from a few meters to tens of kilometers in radius. Although there is no established definition, cells with a radius of a few meters to tens of meters are called femtocells, cells with a radius of tens to tens of meters are called picocells, cells with a radius of tens to hundreds of meters are called microcells, and cells with a radius of more than hundreds of meters are called macrocells. 5G often uses high-frequency radio waves such as millimeter waves, and because of their high line-propagation ability, radio waves can be blocked by obstacles, shortening the communication distance. For this reason, 5G tends to use smaller cells than 4G and earlier generations.

[0018] A communication device 2 can perform 5G communication if it is located within at least one of multiple 5G cells 112A, 112B, and 112C. In the illustrated example, a communication device 2B located within 5G cells 112A and 112B can communicate with both 5G base stations 111A and 111B via 5G NR. Furthermore, a communication device 2C located within 5G cell 112C can communicate with 5G base station 111C via 5G NR. Communication devices 2A and 2D are located outside all of the 5G cells 112A, 112B, and 112C and are therefore unable to communicate via 5G NR. 5G communication via 5G NR between each communication device 2 and each 5G base station 111 is managed by the 5GC, which is a core network. For example, the 5GC handles data transmission and reception between each 5G base station 111, data transmission and reception between EPC, a satellite communication system 13, and external networks such as the Internet, and mobility management of the communication device 2.

[0019] The 4G wireless communication system 12 includes multiple 4G base stations 121 (only one of which is shown in FIG. 1 ) that are installed on the ground and capable of communicating with the communication device 2 via LTE or LTE-Advanced. In 4G, the base station 121 is also called an eNodeB (eNB). Like each 5G base station 111, the coverage area or support area of ​​each 4G base station 121 is also called a cell, and is illustrated as 122.

[0020] If the communication device 2 is located inside the 4G cell 122, it can perform 4G communication. In the illustrated example, communication devices 2A and 2B located inside the 4G cell 122 can communicate with the 4G base station 121 via LTE or LTE-Advanced. Communication devices 2C and 2D are located outside the 4G cell 122 and are therefore unable to communicate via LTE or LTE-Advanced. 4G communication between each communication device 2 and each 4G base station 121 via LTE or LTE-Advanced is managed by the EPC, which is a core network. For example, the EPC handles the exchange of data with each 4G base station 121, the exchange of data with external networks such as 5GC, the satellite communication system 13, and the Internet, and the mobility management of the communication device 2.

[0021] Focusing on each of the communicators 2A, 2B, 2C, and 2D, in the illustrated example, communicator 2A is capable of 4G communication with 4G base station 121, communicator 2B is capable of 5G communication with 5G base stations 111A and 111B and 4G communication with 4G base station 121, and communicator 2C is capable of 5G communication with 5G base station 111C. In cases where there are multiple base stations (111A, 111B, 121) with which communicator 2B can communicate, one base station determined to be optimal in terms of communication quality, etc., is selected under the management of the 5G communication center (5GC) and / or the EPC core network, and communication with communicator 2B is performed. Furthermore, communicator 2D is not capable of communication with any of the 5G base stations 111 and 4G base station 121, and therefore performs communication via satellite communication system 13, which will be described next.

[0022] The satellite communication system 13 is a wireless communication system that uses a communication satellite 131, which is a low-orbit satellite flying in space at an altitude of approximately 500 km to 700 km above the Earth's surface, as a non-terrestrial base station. Similar to the 5G base station 111 and the 4G base station 121, the communication range or support area of ​​the communication satellite 131 is also called a cell and is illustrated as 132. In this way, the communication satellite 131, which is a non-terrestrial base station, provides the satellite communication cell 132, which is a non-terrestrial communication cell, to the ground. A terrestrial communication device 2 can perform satellite communication if it is located inside the satellite communication cell 132. Similar to the 5G base station 111 in the 5G wireless communication system 11 and the 4G base station 121 in the 4G wireless communication system 12, the communication satellite 131, which is a base station in the satellite communication system 13, can wirelessly communicate with the communication device 2 in the satellite communication cell 132 directly or indirectly via an aircraft or the like. The radio access technology that the communication satellite 131 uses for radio communication with the communication device 2 in the satellite communication cell 132 may be 5G NR, the same as the 5G base station 111, or LTE or LTE-Advanced, the same as the 4G base station 121, or any other radio access technology that can be used by the communication device 2. Therefore, the communication device 2 does not need to be provided with special functions or components for satellite communication.

[0023] The satellite communication system 13 includes a gateway 133 as a ground station installed on the ground and capable of communicating with a communication satellite 131. The gateway 133 includes a satellite antenna for communicating with the communication satellite 131, and is connected to a 5G base station 111 and a 4G base station 121 as terrestrial base stations that constitute a terrestrial network (TN). In this way, the gateway 133 connects the non-terrestrial network (NTN) formed by the communication satellite 131 as a non-terrestrial base station or satellite base station and the TN formed by the terrestrial base stations 111 and 121 so that they can communicate with each other. When the communication satellite 131 performs 5G communication with the communication device 2 in the satellite communication cell 132 using 5G NR, the 5GC connected via the gateway 133 and the 5G base station 111 (or a 5G radio access network) in the TN is used as the core network, and when the communication satellite 131 performs 4G communication with the communication device 2 in the satellite communication cell 132 using LTE or LTE-Advanced, the EPC connected via the gateway 133 and the 4G base station 121 (or a 4G radio access network) in the TN is used as the core network. In this way, appropriate cooperation is achieved between different wireless communication systems such as 5G communication, 4G communication, and satellite communication via the gateway 133.

[0024] Satellite communication using a communication satellite 131 is primarily used to cover areas where terrestrial base stations such as 5G base station 111 and 4G base station 121 are not installed or are few in number. In the illustrated example, a communication device 2D located outside the communication cells of all terrestrial base stations communicates with the communication satellite 131. Meanwhile, communication devices 2A, 2B, and 2C that can communicate satisfactorily with any terrestrial base station are also within a satellite communication cell 132 and can therefore communicate with the communication satellite 131. However, by communicating with a terrestrial base station rather than the communication satellite 131 as a satellite base station, the limited communication resources (including power) of the communication satellite 131 are conserved for the communication device 2D and the like. The communication satellite 131 improves the quality of communication with the communication device 2D by directing communication radio waves toward the communication device 2D within the satellite communication cell 132 using beamforming.

[0025] The size of the satellite communication cell 132 of the communication satellite 131 serving as a satellite base station can be set arbitrarily depending on the number of beams emitted by the communication satellite 131; for example, a satellite communication cell 132 with a diameter of approximately 24 km can be formed by combining up to 2,800 beams. As shown in the figure, the satellite communication cell 132 is typically larger than a terrestrial communication cell such as the 5G cell 112 or the 4G cell 122, and may include one or more 5G cells 112 and / or 4G cells 122 therein. Note that, although the above example illustrates a communication satellite 131 flying in low orbit at an altitude of approximately 500 km to 700 km above the Earth's surface as a flying non-terrestrial base station, a communication satellite flying in high orbit such as a geostationary orbit, or an unmanned or manned aircraft flying in the atmosphere at a lower altitude (for example, approximately 20 km above the Earth's surface) such as the stratosphere, may also be used as a non-terrestrial base station in addition to or instead of the communication satellite 131.

[0026] FIG. 2 shows a schematic diagram of an example of a location registration area or tracking area (denoted as "TA" in FIG. 2) that is configured by terrestrial communication cells 112 and 122 (denoted as "TN Cell" in FIG. 2) provided to the ground by terrestrial base stations 111 and 121 installed on the ground and a non-terrestrial communication cell 132 (denoted as "NTN Cell" in FIG. 2) provided to the ground by an airborne non-terrestrial base station 131. The location registration area or tracking area is set to track or detect the approximate location of a communication device 2. Each location registration area is configured by one or more base stations 111, 121, and 131. Specifically, the entire area of ​​the communication cells 112, 122, and 132 provided to the ground by the base stations 111, 121, and 131 corresponds to each location registration area. For example, a Japanese mobile network operator (MNO) covers the entire country of Japan with dozens of location registration areas.

[0027] In Figure 2, the first location registration area TA1 is a location registration area consisting of one or more (multiple in Figure 2) terrestrial communication cells 112, 122 that are geographically adjacent or nearby, the second location registration area TA2 is a location registration area consisting of one or more (one in Figure 2) non-terrestrial communication cells 132 that are geographically adjacent or nearby, and the third location registration area TA3 is a location registration area consisting of one or more (multiple in Figure 2) terrestrial communication cells 112, 122 that are geographically adjacent or nearby.

[0028] Each location registration area TA1 to TA3 is assigned a code or ID called a Tracking Area Code (TAC) that uniquely identifies the location registration area, and is simply indicated as "#1" to "#3" in FIG. 2. Specifically, the TAC or ID of the first location registration area TA1 is "#1," the TAC or ID of the second location registration area TA2 is "#2," and the TAC or ID of the third location registration area TA3 is "#3." However, as will be described later, the TAC or ID of the second location registration area TA2 may be set to "#1," the same as that of the first location registration area TA1. In this way, one location registration area may include communication cells of different types (terrestrial communication cells 112, 122 and non-terrestrial communication cell 132). In the example of Figure 2, communication device 2E is located within the first location registration area TA1, communication device 2F is located within the overlapping area of ​​the first location registration area TA1 and the second location registration area TA2, communication device 2G is located within the second location registration area TA2, communication device 2H is located within the overlapping area of ​​the second location registration area TA2 and the third location registration area TA3, and communication device 2I is located within the third location registration area TA3 (hereinafter, communication devices 2E to 2I are collectively referred to as communication device 2).

[0029] When a mobile base station represented by the communication satellite 131 moves relative to the communication device 2 (in FIG. 2, particularly, the communication devices 2F, 2G, and 2H in the satellite communication cell 132), the communication device 2 may move outside the satellite communication cell 132 as a mobile communication cell, and transition from "in range" to "out of range" of the communication satellite 131. When a large number of communication devices 2 suddenly become "out of range" in this way, they all simultaneously search for and attempt to connect to other available base stations (for example, the 5G base station 111 or the 4G base station 121), which results in a concentrated increase in the signal processing load on the core network side.

[0030] In particular, if the TAC "#2" of the second location registration area TA2 formed by the non-terrestrial communication cell 132 is different from the TAC "#1" of the first location registration area TA1 formed by the terrestrial communication cells 112 and 122 and the TAC "#3" of the third location registration area TA3, when communication devices 2 (2F, 2G, 2H) that are "out of range" of the non-terrestrial communication cell 132 simultaneously register or connect to the terrestrial communication cells 112 and 122, a change in location registration area (from "#2" to "#1" or from "#2" to "#3") occurs, and the core network must process a large number of area change notifications or location registration area update notifications (TA Update: Tracking Area Update), which further increases the signal processing load on the core network.

[0031] A similar situation to the above may occur, for example, when the base stations 111, 121, and 131, which have limited operating times, transition from an operating state to a stopped state. That is, when the base stations 111, 121, and 131 transition to a stopped state, a large number of communication devices 2 may simultaneously transition from "in range" to "out of range" of the base stations 111, 121, and 131, resulting in a concentrated increase in the signal processing load on the core network side. This embodiment aims to provide a communication control device 3 that can alleviate the concentration of the signal processing load on the core network side caused by changes in the operating states of the base stations 111, 121, and 131. The "operating state" of the base stations 111, 121, and 131 is not limited to the narrowly defined operating state and stopped state described above, but also encompasses the position and movement state of mobile base stations moving in the air or on the ground.

[0032] FIG. 3 is a functional block diagram of the communication control device 3 according to this embodiment. The communication control device 3 includes an operation schedule acquisition unit 31, a communication device identification unit 32, and a connection control unit 33. Some of these functional blocks may be omitted as long as the communication control device 3 achieves at least some of the functions and / or effects described below. These functional blocks are realized by the cooperation of hardware resources, such as a computer's central processing unit, memory, input devices, output devices, and peripheral devices connected to the computer, and software executed using these resources. Regardless of the type and location of the computer, each of the above functional blocks may be realized by the hardware resources of a single computer or by a combination of hardware resources distributed across multiple computers. In particular, in this embodiment, some or all of the functional blocks of the communication control device 3 may be realized in a centralized or distributed manner by computers and processors provided in the communication device 2, base stations 111, 121, and 131, or a core network (not shown).

[0033] In the illustrated example, two groups of communication devices that are in an idle state (a connection standby state) with respect to the non-terrestrial base station 131 are sequentially connected to the terrestrial base stations 111 and 121 before the non-terrestrial base station 131 goes "out of range." However, the scope of application of the present disclosure is not limited to the illustrated example. For example, in the illustrated example, the "transition source" base station, which is the flying non-terrestrial base station 131, may be the terrestrial base stations 111 and 121 that are fixedly installed on the ground, or may be a terrestrial mobile base station (not shown) that moves on the ground. Also, in the illustrated example, the "transition destination" base station (another base station), which is the terrestrial base station 111 and 121 that are fixedly installed on the ground, may be the flying non-terrestrial base station 131, or may be a terrestrial mobile base station (not shown) that moves on the ground.

[0034] The operation schedule acquisition unit 31 acquires the operation schedule of the non-terrestrial base station 131 that is the transition source. Specifically, the operation schedule acquisition unit 31 acquires the movement schedule of the non-terrestrial base station 131 as a mobile base station that moves relative to the communication device 2, and the operation time of the non-terrestrial base station 131. The movement schedule of the non-terrestrial base station 131 is managed on the core network side, for example, in the form of orbital information or operation information of the communication satellite 131. Such orbital information may be acquired from a GPS module or the like mounted on the communication satellite 131 itself, or may be acquired from a positioning module that remotely positions the communication satellite 131. Furthermore, the operation time of the non-terrestrial base station 131 is managed on the core network side, for example, in the form of an operation schedule that includes the operation time and stop time of the communication satellite 131. Such an operation schedule may be notified to the terrestrial base stations 111, 121, the gateway 133, the communication device 2, etc. from the communication satellite 131 itself or the core network.

[0035] The communicator identifying unit 32 identifies one or more communicators 2 that are in a connection standby state (idle state) with the non-terrestrial base station 131 that is the transition source, and that may transition to a state in which connection with the non-terrestrial base station 131 is unavailable, according to the operation schedule of the non-terrestrial base station 131 acquired by the operation schedule acquisition unit 31. For example, the communicator identifying unit 32 identifies a communicator 2 that is in a connection standby state (idle state) with the non-terrestrial base station 131 that serves as a mobile base station, and that may be outside the non-terrestrial communication cell 132 (mobile communication cell) provided by the non-terrestrial base station 131, according to the movement schedule of the non-terrestrial base station 131 acquired by the operation schedule acquisition unit 31. In the example of FIG. 2, the communicator identifying unit 32 identifies communicators 2F, 2G, and 2H that may relatively move from the inside to the outside of the satellite communication cell 132 as the communication satellite 131 passes through. Furthermore, the communication device identification unit 32 identifies communication devices 2 (in the example of Figure 2, communication devices 2F, 2G, and 2H, as above) that are in a state of waiting for connection (idle state) with the non-terrestrial base station 131 and that may transition to a state in which they cannot connect to the non-terrestrial base station 131 when the non-terrestrial base station 131 falls outside the operating hours (i.e., within the stop time) acquired by the operation schedule acquisition unit 31.

[0036] Specifically, the communication device identifying unit 32 may measure the position of each communication device 2 using a GPS module or the like mounted on each communication device 2 itself, may measure the position using a beacon or other positioning module that positions each communication device 2, or may recognize the position from various location-related information managed on the core network side, such as location information managed by a TAC or LMF (Location Management Function).By comparing this location information of each communication device 2 with trajectory information, operation information, and the like of the non-terrestrial base station 131 acquired by the operation schedule acquiring unit 31, the communication device identifying unit 32 can accurately predict the time at which each communication device 2 will transition to a state in which it cannot connect to the non-terrestrial base station 131.

[0037] The connection control unit 33 transitions one or more communication devices 2 in an idle state with respect to the non-terrestrial base station 131 identified by the communication device identifying unit 32 from the idle state to a connected state with the non-terrestrial base station 131 and / or the terrestrial base stations 111 and 121 (other base stations) before transitioning to a state in which connection to the non-terrestrial base station 131 is not possible. In other words, the communication devices 2 in an idle state with respect to the non-terrestrial base station 131 are forcibly transitioned from the idle state to a connected state before transitioning to a state in which connection to the non-terrestrial base station 131 is not possible. Specifically, the connection control unit 33 forcibly transitions the communication devices 2 identified by the communication device identifying unit 32 from the idle state to a connected state before the communication devices 2 go outside the non-terrestrial communication cell 132 as a mobile communication cell and / or before the non-terrestrial base station 131 goes out of operation. Note that the connection control unit 33 may restrict or prohibit the communication devices 2 that have been forcibly transitioned to the connected state from transitioning to the idle state for at least a predetermined time.

[0038] In this way, the communication device 2 can start searching for other base stations (terrestrial base stations 111, 121) before going "out of range" (connection-disabled state) of the non-terrestrial base station 131, thereby alleviating the concentration of signal processing load on the core network side. Note that the communication device 2 that is forcibly transitioned to a connected state by the connection control unit 33 may directly connect to the destination terrestrial base station 111, 121 without reconnecting to the source non-terrestrial base station 131, or may search for the destination terrestrial base station 111, 121 after reconnecting to the source non-terrestrial base station 131.

[0039] As shown in the illustrated example, when the TAC "#2" of the location registration area of ​​the non-terrestrial communication cell 132 (non-terrestrial base station 131) as a transition source is different from the TACs "#1" and "#3" of the location registration areas of the terrestrial communication cells 112 and 122 (terrestrial base stations 111 and 121) as a transition destination, a change in location registration area occurs when a communication device 2 that is "out of range" of the non-terrestrial communication cell 132 registers or connects to the terrestrial communication cell 112 or 122, and therefore the core network needs to process area change notifications for each communication device 2. However, in this embodiment, each communication device 2 does not simultaneously transition to the terrestrial communication cells 112 and 122 the moment it becomes "out of range" of the non-terrestrial communication cell 132, but can transition to the terrestrial communication cell 112 or 122 with sufficient time to do so before it becomes "out of range" of the non-terrestrial communication cell 132. In this way, it is possible to prevent area change notifications from each communication device 2 from concentrating at the moment it becomes "out of range" of the non-terrestrial communication cell 132, thereby mitigating the concentration of signal processing load on the core network side.

[0040] As described above, according to the present embodiment, it is possible to effectively prevent concentration of signal processing loads associated with transition to the terrestrial communication cells 112 and 122 at the moment when the communication device 2 goes "out of range" of the non-terrestrial communication cell 132. To further enhance the effect of distributing such signal processing loads, the connection control unit 33 may divide the plurality of communication devices 2 identified by the communication device identification unit 32 into at least two groups. In the illustrated example, N is a natural number equal to or greater than 2, and the N or more communication devices 2 identified by the communication device identification unit 32 are divided into N groups (first group, second group, ..., Nth group). Each group includes at least one communication device 2. The method for dividing the communication devices 2 by the connection control unit 33 is arbitrary. For example, the plurality of communication devices 2 may be divided into N groups randomly based on random numbers. Alternatively, the grouping may be performed based on identification information of the communication devices 2, such as IMEI (International Mobile Equipment Identity). For example, the communication devices 2 may be divided into N groups according to the remainder (0, 1, . . . N-1) when the IMEI is divided by N.

[0041] The connection control unit 33 may transition each set of communication devices 2 from the idle state to the connected state at different transition times. Specifically, the connection control unit 33 transitions the first set of communication devices 2 from the idle state to the connected state at a first transition time, transitions the second set of communication devices 2 from the idle state to the connected state at a second transition time, and similarly transitions the Nth set of communication devices 2 from the idle state to the connected state at an Nth transition time. Here, the first to Nth transition times are different from one another and are all times before each set of communication devices 2 transitions to a state in which they cannot be connected to the non-terrestrial base station 131. In this way, by shifting the transition times at which each set of communication devices 2 transitions from the idle state to the connected state, the signal processing load on the core network side can be further distributed over time.

[0042] The connection control unit 33 may transition only some of the multiple communication devices 2 identified by the communication device identification unit 32 (for example, the 1st to N-1th sets of communication devices 2) from the idle state to the connected state before transitioning to a state in which connection with the non-terrestrial base station 131 is not possible. In this case, after transitioning to a state in which connection with the non-terrestrial base station 131 is not possible, the Nth set of communication devices 2 searches for and attempts to connect to other available base stations (terrestrial base stations 111, 121), but this does not substantially overlap with the signal processing related to the transition of the other 1st to N-1th sets of communication devices 2, and therefore it is possible to avoid a situation in which the signal processing load on the core network side increases in a concentrated manner.

[0043] The present disclosure has been described above based on the embodiments. Various modifications are possible to the combinations of the components and processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included within the scope of the present disclosure.

[0044] In the embodiment, a case has been described in which the non-terrestrial base station 131 as a mobile base station moves relative to the communication device 2. However, similar processing can be applied to a case in which the communication device 2 moves relative to, for example, the terrestrial base stations 111 and 121 as fixed base stations. For example, the operation schedule acquisition unit 31 recognizes the positions of the terrestrial base stations 111 and 121 and the communication ranges of the terrestrial communication cells 112 and 122, and the communication device identification unit 32 recognizes the position and movement schedule of each communication device 2. By comparing such information related to the terrestrial base stations 111 and 121 with information related to each communication device 2, the communication device identification unit 32 can accurately predict the time at which each communication device 2 will transition to an unconnectable state with the terrestrial base station 111 or 121. Then, the connection control unit 33 forcibly transitions the communication device 2, which is in an idle state with respect to the terrestrial base station 111 or 121, from the idle state to a connected state before the communication device 2 transitions to an unconnectable state with the terrestrial base station 111 or 121.

[0045] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources, software resources, or a combination of hardware and software resources. Examples of hardware resources include processors, ROMs, RAMs, and various integrated circuits. Examples of software resources include operating systems, applications, and other programs.

[0046] The present disclosure may be expressed in the following terms:

[0047] Item 1: acquiring an operation schedule of the base station by an operation schedule acquisition unit; Identifying, by a communication device identifying unit, a communication device that is in a connection standby state with the base station and that may transition to a connection unavailable state with the base station according to the operation schedule; transitioning the communication device from the connection standby state to a connection state with the base station and / or another base station by a connection control unit before transitioning to the connection unavailable state; A communication control device comprising at least one processor that executes the above. Item 2: the base station is a mobile base station that moves relative to the communication device; the operation schedule acquisition unit acquires a movement schedule of the mobile base station, the communication device specifying unit specifies a communication device that is in a standby state for connection with the mobile base station and that may be outside a mobile communication cell provided by the mobile base station according to the movement schedule; the connection control unit transitions the communication device from the connection standby state to a connection state with the mobile base station and / or another base station before the communication device goes out of the mobile communication cell; Item 1. The communication control device according to item 1. Item 3: 3. The communication control device according to item 2, wherein the mobile base station is an airborne non-terrestrial base station. Item 4: 4. The communication control device according to item 3, wherein the non-terrestrial base station is a communication satellite flying in outer space. Item 5: 5. The communication control device according to any one of items 1 to 4, wherein the other base station is a terrestrial base station that is fixedly installed on the ground. Item 6: the operation schedule acquisition unit acquires an operation time of the base station; the communication device identifying unit identifies a communication device that is in a standby state for connection with the base station and that may transition to a state in which connection with the base station is disabled when the base station is outside the operating hours; the connection control unit transitions the communication device from the connection standby state to a connection state with the base station and / or another base station before the base station goes out of the operating time. 6. A communication control device according to any one of items 1 to 5. Item 7: the communication device specifying unit specifies a plurality of communication devices that are in a standby state for connection with the base station and that may transition to a state in which connection with the base station is unavailable in accordance with the operation schedule; the connection control unit divides the plurality of communication devices into at least two groups, a first group that transitions the plurality of communication devices to the connected state at a first transition time before the transition to the unconnectable state, and a second group that transitions the plurality of communication devices to the connected state at a second transition time before the transition to the unconnectable state and different from the first transition time; 7. A communication control device according to any one of items 1 to 6. Item 8: 8. The communication control device according to item 7, wherein the connection control unit divides the plurality of communication devices into the first group and the second group based on a random number. Item 9: the communication device specifying unit specifies a plurality of communication devices that are in a standby state for connection with the base station and that may transition to a state in which connection with the base station is unavailable in accordance with the operation schedule; the connection control unit transitions some of the plurality of communication devices to the connected state before transitioning to the unconnectable state; 9. A communication control device according to any one of items 1 to 8. Item 10: 10. The communication control device according to any one of items 1 to 9, wherein the base station and the other base station belong to different location registration areas. Item 11: Obtaining a base station operation schedule; Identifying a communication device that is in a standby state for connection with the base station and that may transition to a state in which connection with the base station is unavailable according to the operation schedule; transitioning the communication device from the connection waiting state to a connection state with the base station and / or another base station before transitioning to the connection unavailable state; A communication control method comprising: Item 12: Obtaining a base station operation schedule; Identifying a communication device that is in a standby state for connection with the base station and that may transition to a state in which connection with the base station is unavailable according to the operation schedule; transitioning the communication device from the connection waiting state to a connection state with the base station and / or another base station before transitioning to the connection unavailable state; A storage medium that stores a communication control program that causes a computer to execute the above. [Explanation of symbols]

[0048] 1 wireless communication system, 2 communication device, 3 communication control device, 11 5G wireless communication system, 12 4G wireless communication system, 13 satellite communication system, 31 operation schedule acquisition unit, 32 communication device identification unit, 33 connection control unit, 111 5G base station, 112 5G cell, 121 4G base station, 122 4G cell, 131 communication satellite, 132 satellite communication cell, 133 gateway.

Claims

1. an operation schedule acquisition unit that acquires an operation schedule of a communications satellite; a communication device identification unit that identifies a communication device that is in a standby state for connection with the communication satellite and that may be outside a satellite communication cell provided by the communication satellite according to the flight schedule of the communication satellite as the operation schedule and transition to a state in which connection with the communication satellite is unavailable; a connection control unit that transitions the communication device from the connection standby state with the communication satellite to a connection state with a terrestrial base station that is fixedly installed on the ground before the communication device leaves the satellite communication cell; A communication control device comprising:

2. the operation schedule acquisition unit acquires an operation time of the communication satellite, the communication device identifying unit identifies a communication device that is in a standby state for connection with the communication satellite and that may transition to a state in which connection with the communication satellite is disabled when the communication satellite is out of the operating hours; the connection control unit transitions the communication device from the connection standby state to a connection state with the terrestrial base station before the communication satellite goes out of operation. The communication control device according to claim 1 .

3. the communication device identifying unit identifies a plurality of communication devices that are in a standby state for connection with the communication satellite and that may transition to a state in which connection with the communication satellite is unavailable in accordance with the operation schedule; the connection control unit divides the plurality of communication devices into at least two groups, a first group that transitions the plurality of communication devices to the connected state at a first transition time before the transition to the unconnectable state, and a second group that transitions the plurality of communication devices to the connected state at a second transition time before the transition to the unconnectable state and different from the first transition time; The communication control device according to claim 1 .

4. The communication control device according to claim 3 , wherein the connection control unit divides the plurality of communication devices into the first group and the second group based on a random number.

5. the communication device identifying unit identifies a plurality of communication devices that are in a standby state for connection with the communication satellite and that may transition to a state in which connection with the communication satellite is unavailable in accordance with the operation schedule; the connection control unit transitions some of the plurality of communication devices to the connected state before transitioning to the unconnectable state; The communication control device according to claim 1 .

6. The communication control device according to claim 1 , wherein the communication satellite and the terrestrial base station belong to different location registration areas.

7. Obtaining the operational schedule of the communications satellite; Identifying a communication device that is in a standby state for connection with the communication satellite and that may transition to a state in which it is unable to connect to the communication satellite due to being outside a satellite communication cell provided by the communication satellite according to the flight schedule of the communication satellite as the operation schedule; transitioning the communication device from the connection standby state with the communication satellite to a connection state with a terrestrial base station that is fixedly installed on the ground before the communication device leaves the satellite communication cell; A communication control method comprising:

8. Obtaining the operational schedule of the communications satellite; Identifying a communication device that is in a standby state for connection with the communication satellite and that may transition to a state in which it is unable to connect to the communication satellite due to being outside a satellite communication cell provided by the communication satellite according to the flight schedule of the communication satellite as the operation schedule; transitioning the communication device from the connection standby state with the communication satellite to a connection state with a terrestrial base station that is fixedly installed on the ground before the communication device leaves the satellite communication cell; A communication control program that causes a computer to execute the above.

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