Controlling operation state of ground base station via non-ground base station

Abstract

To provide a communication control device, a method, and a storage medium that can reduce power wastage in a ground base station.SOLUTION: A communication control device 3 includes a communication device detection unit 31 that detects a communication device 2 within a satellite communication cell 132 provided to the ground by a flying communication satellite 131, a ground communication cell detection unit 32 that detects ground communication cells 112, 122 that can be provided to the ground by ground base stations 111, 121 installed on the ground, and a ground base station operation state control unit 33 that controls the operation state of the ground base station based on detection results of the communication device detection unit and the ground communication cell detection unit. The ground communication cell detection unit and the ground base station operation state control unit are provided in a gateway 133 that is installed on the ground and capable of communicating with the communication satellite. The ground communication cell detection unit obtains information about the ground communication cell through an inter-station interface IF between the gateway and the ground base station, and the ground base station operation state control unit controls the operation state of the ground base station through the inter-station interface IF.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to controlling the operation state of terrestrial base stations via non-terrestrial base stations in a communication system. [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 on the ground 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] For example, if a non-terrestrial communication cell using a non-terrestrial base station is provided in a sparsely populated area, and a terrestrial communication cell using a terrestrial base station is also provided in such an area, it is possible that there may be no communication device connected to the terrestrial base station within the terrestrial communication cell. In such cases, the power of the operating terrestrial base station will be wasted.

[0007] The present disclosure has been made in view of these circumstances, and its purpose is to provide a communication control device and the like that can reduce the power wasted in a terrestrial base station. [Means for solving the problem]

[0008] In order to solve the above problems, a communication control device according to one aspect of the present disclosure includes a communication device detection unit that detects a communication device within a non-terrestrial communication cell provided to the ground by a flying non-terrestrial base station, a terrestrial communication cell detection unit that detects a terrestrial communication cell that can be provided to the ground by a terrestrial base station installed on the ground, and a terrestrial base station operation status control unit that controls the operation status of the terrestrial base station based on the detection results of the communication device detection unit and the terrestrial communication cell detection unit.

[0009] In this aspect, the operation state of the terrestrial base station is controlled based on the detection result of the terrestrial communication cell that can be provided to the ground by the communication device and the terrestrial base station in the non-terrestrial communication cell. For example, if the communication device can communicate with the non-terrestrial base station in the non-terrestrial communication cell without any particular problems, the operation state of the terrestrial base station that can provide the terrestrial communication cell in or around the non-terrestrial communication cell is set to a communication suspension state.

[0010] Another aspect of the present disclosure is a communication control method, which includes detecting a communication device within a non-terrestrial communication cell provided to the ground by an airborne non-terrestrial base station, detecting a terrestrial communication cell that can be provided to the ground by a terrestrial base station installed on the ground, and controlling an operation state of the terrestrial base station based on the detection results of the communication device and the terrestrial communication cell.

[0011] Yet another aspect of the present disclosure is a storage medium that stores a communication control program that causes a computer to execute the following operations: detecting a communication device within a non-terrestrial communication cell provided to the ground by an airborne non-terrestrial base station; detecting a terrestrial communication cell that can be provided to the ground by a terrestrial base station installed on the ground; and controlling the operating state of the terrestrial base station based on the detection results of the communication device and the terrestrial communication cell.

[0012] Any combination of the above components, and conversion of the present disclosure into a method, device, system, recording medium, computer program, etc., are also valid aspects of the present disclosure. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to reduce the power wasted in terrestrial 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] FIG. 2 is a functional block diagram of a communication control device. DETAILED DESCRIPTION OF THE INVENTION

[0015] The communication control device according to the present disclosure can be applied to a network in which a terrestrial network (TN: Terrestrial Network) constructed by terrestrial communication cells provided to the ground by terrestrial base stations installed on the ground, and a non-terrestrial network (NTN: Non-Terrestrial Network) constructed by non-terrestrial communication cells provided to the ground by flying non-terrestrial base stations coexist.

[0016] 1 is a schematic diagram illustrating an overview of a wireless communication system 1 to which a communication control device according to this embodiment is applied. The wireless communication system 1 includes a 5G wireless communication system 11 that conforms 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 that conforms 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 handles 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 that is not associated with a generation, such as Wi-Fi (registered trademark).

[0017] 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).

[0018] 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 several hundred meters are called macrocells. 5G often uses high-frequency radio waves such as millimeter waves, and because of their high line-of-sight characteristics, the radio waves are blocked by obstacles, shortening the communication distance. For this reason, 5G tends to use smaller cells than 4G and earlier generations.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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 via their respective wireless access technologies, such as 5G NR or LTE, or other wired or wireless access technologies or interfaces. In this way, the gateway 133 connects the NTN formed by the communication satellite 131 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.

[0025] 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.

[0026] The size of the satellite communication cell 132 of the communication satellite 131 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 4G cell 122, and can include one or more 5G cells 112 and / or 4G cells 122 therein. In the above, a communication satellite 131 flying in space in a low earth orbit (LEO: Low Earth Orbit) at an altitude of about 500 km to 700 km above the earth's surface has been used as an example of a flying non-terrestrial base station, but a communication satellite flying in space in a higher orbit such as a geosynchronous equatorial orbit (GEO: Geosynchronous Equatorial Orbit) or an unmanned or manned aircraft flying in the atmosphere at a lower altitude (for example, about 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.

[0027] As described above, the wireless communication system 1 according to this embodiment includes terrestrial networks (TN) 11, 12 capable of communicating with the communication devices 2 in terrestrial communication cells 112, 122 provided on the ground by terrestrial base stations 111, 121 installed on the ground, and a non-terrestrial network (NTN) 13 capable of communicating with the communication devices 2 in a non-terrestrial communication cell 132 provided on the ground by an airborne non-terrestrial base station 131. The communication control device according to this embodiment controls the TN and the NTN.

[0028] FIG. 2 is a functional block diagram of a communication control device 3 according to this embodiment. The communication control device 3 includes a communication device detection unit 31, a terrestrial communication cell detection unit 32, and a terrestrial base station operational status control unit 33. 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 combining hardware resources distributed across multiple computers. For example, some or all of the functional blocks of the communication control device 3 may be realized in a distributed or centralized manner by computers and processors provided in the communication device 2, the terrestrial base stations 111 and 121, the non-terrestrial base station 131, the gateway 133, and the core network CN. As will be described later, in the example of FIG. 2, the terrestrial communication cell detection unit 32 and the terrestrial base station operational status control unit 33 are provided in the gateway 133. However, in other examples, some or all of these functional blocks may be realized by computers and processors provided outside the gateway 133.

[0029] The communication device detection unit 31 detects a communication device 2 within a satellite communication cell 132 provided to the ground by a communication satellite 131. FIG. 2 exemplarily and schematically illustrates four communication devices 2E-2H (collectively referred to as communication devices 2 as before) corresponding to four types of information detected by the communication device detection unit 31. The following describes the four types of information related to the four communication devices 2E-2H individually, but in actual operation of the wireless communication system 1, any combination of these types of information can be used for communication control. The communication device detection unit 31 includes a random access information detection unit 311, a communication device movement detection unit 312, a communication device position detection unit 313, and a service quality request detection unit 314 to detect each of the four types of information related to the communication device 2. These four detection units 311-314 are merely shown as separate functional units for the sake of convenience of explanation, but may actually be configured as an integral, inseparable functional unit, hardware, software, artificial intelligence, or the like.

[0030] The random access information detection unit 311 detects a communication device 2E in the satellite communication cell 132 based on random access information transmitted from the communication device 2E to the communication satellite 131. A communication device 2E that is powered on in the satellite communication cell 132, or a communication device 2E that has entered the satellite communication cell 132 from an "out of range" state until just before, executes a predetermined random access procedure with the communication satellite 131 to start mobile communication with NTN. A typical random access procedure in 4G or 5G starts with the communication device 2E transmitting a random access preamble (hereinafter simply referred to as a preamble) as random access information to the communication satellite 131.

[0031] The communication device 2E selects any one preamble from a limited number (for example, 64) of mutually orthogonal preambles that the communication satellite 131 can receive, and transmits the selected preamble to the communication satellite 131 using a predetermined time-frequency resource reserved as a Physical Random Access Channel (PRACH) in each uplink frame for preamble transmission. The random access information detection unit 311 detects that the communication device 2E is located within the satellite communication cell 132 based on the preamble thus transmitted by the communication device 2E to the communication satellite 131. The random access information detection unit 311 may be provided in the communication satellite 131 that directly receives the preamble from the communication device 2E, or may be provided in the gateway 133 or core network CN that can communicate with the communication satellite 131.

[0032] The communication device movement detection unit 312 detects movement of the communication device 2F within the satellite communication cell 132. Specifically, as will be described later with respect to the terrestrial base station operation state control unit 33, the terrestrial base stations 111, 121 that provide the terrestrial communication cells 112, 122 are controlled to different operation states depending on whether the communication device 2F is moving toward the terrestrial communication cells 112, 122 inside or outside the satellite communication cell 132. The movement of the communication device 2F is detected, for example, by a satellite positioning device such as a GPS module mounted on the communication device 2F, and is notified from the communication device 2F to the communication satellite 131. In this case, the communication device movement detection unit 312 may be provided in the communication satellite 131 that directly receives satellite positioning information from the communication device 2F, or may be provided in a gateway 133 or a core network CN that can communicate with the communication satellite 131. Information regarding the movement of the communication device 2F may be acquired via an LMF (Location Management Function) provided in 5GC, which is a 5G core network CN.

[0033] The communication device position detection unit 313 detects the position of the communication device 2G within the satellite communication cell 132. Specifically, as will be described later with reference to the terrestrial base station operation state control unit 33, the terrestrial base stations 111, 121 that provide the terrestrial communication cells 112, 122 are controlled to different operation states depending on whether the position of the communication device 2G is within a predetermined distance range 112′, 122′ from the terrestrial communication cells 112, 122 inside or outside the satellite communication cell 132. The position of the communication device 2G is detected, for example, by a satellite positioning device such as a GPS module mounted on the communication device 2G, and is notified from the communication device 2G to the communication satellite 131. In this case, the communication device position detection unit 313 may be provided in the communication satellite 131 that directly receives satellite positioning information from the communication device 2G, or may be provided in the gateway 133 or core network CN that can communicate with the communication satellite 131. Information regarding the position of the communication device 2G may also be acquired via an LMF provided in the 5GC.

[0034] The service quality request detection unit 314 detects a service quality request of the communication device 2H in the satellite communication cell 132. Specifically, as will be described later with reference to the terrestrial base station operation state control unit 33, when the communication device 2H connected to the communication satellite 131 in the overlapping area of ​​the satellite communication cell 132 and the terrestrial communication cells 112, 122 performs emergency communication such as an emergency call, or prioritized communication with high QoS (Quality of Service) requirements such as VoLTE in 4G or VoNR in 5G, and the communication satellite 131 cannot satisfy the QoS requirements, the terrestrial base stations 111, 121 that provide the terrestrial communication cells 112, 122 are controlled to an operation state in which communication with the communication device 2H is possible. The service quality request detection unit 314 may be provided in the communication satellite 131 that directly receives a service request such as prioritized communication from the communication device 2H, or may be provided in the gateway 133 or core network CN that can communicate with the communication satellite 131. In addition, information regarding the service quality requirements of the communication device 2H may be obtained through a core network CN involved in providing various services to the communication device 2H, or through a server of a service provider that provides various services to the communication device 2H over a general network such as the Internet.

[0035] In addition to or instead of the four types of information related to the communication device 2, the communication device detection unit 31 may detect the location registration area or tracking area (TA) of the communication device 2. A location registration area set to track or detect the approximate location of the communication device 2 is typically made up of multiple communication cells. The location registration area of ​​each communication device 2 is registered in the HLR (Home Location Register) or the like in the core network CN in the form of a TAC (Tracking Area Code) or the like. For the communication devices 2E to 2H in the satellite communication cell 132 illustrated in FIG. 2, a TAC indicating the location registration area to which the satellite communication cell 132 belongs is registered in the HLR. If this location registration area also includes other communication cells (not shown), it is not possible to determine whether each communication device 2 is in the satellite communication cell 132 or another communication cell (not shown) based solely on the TAC acquired by the communication device detection unit 31, but it is possible to determine at least that each communication device 2 is in the vicinity of the satellite communication cell 132. Furthermore, the communication device detection unit 31 may detect that each communication device 2 is located within the satellite communication cell 132 by detecting a connection state in which each communication device 2 is connected to the communication satellite 131 .

[0036] The terrestrial communication cell detection unit 32 detects terrestrial communication cells 112, 122 that can be provided on the ground by the terrestrial base stations 111, 121. In particular, in this embodiment, the detected terrestrial communication cells are terrestrial communication cells 112, 122 that are entirely included in the satellite communication cell 132 (that entirely overlap with the satellite communication cell 132), terrestrial communication cells 112, 122 that are partially included in the satellite communication cell 132 (that partially overlap with the satellite communication cell 132), and terrestrial communication cells 112, 122 provided in a peripheral area adjacent to or close to the satellite communication cell 132 (for example, terrestrial communication cells 112, 122 outside the satellite communication cell 132 that belong to the same location registration area as the satellite communication cell 132). These terrestrial communication cells 112, 122 are hereinafter collectively referred to as NTN-peripheral terrestrial communication cells 112, 122. The terrestrial communication cell detection unit 32 is provided in a gateway 133 serving as a terrestrial station, and acquires information such as the coverage area of ​​each NTN-surrounding terrestrial communication cell 112, 122 from the terrestrial base stations 111, 121 via an inter-station interface IF between the gateway 133 and each terrestrial base station 111, 121. Examples of the inter-station interface IF include the X2 interface and Xn interface in 4G and 5G.

[0037] The terrestrial base station operation state control unit 33 controls the operation states of the terrestrial base stations 111, 121 based on the detection results of the communication device detection unit 31 and the terrestrial communication cell detection unit 32. The main functions of the terrestrial base station operation state control unit 33 are to switch the terrestrial base stations 111, 121 to a communication available state by the communication available state switching unit 331, and to switch the terrestrial base stations 111, 121 to a communication suspended state by the communication suspended state switching unit 332. The terrestrial base stations 111, 121 in a communication available state can communicate with the communication devices 2 in the NTN surrounding terrestrial communication cells 112, 122 provided by the terrestrial base stations 111, 121, and the terrestrial base stations 111, 121 in a communication suspended state cannot communicate with the communication device 2 because they do not provide the NTN surrounding terrestrial communication cells 112, 122.

[0038] The terrestrial base station operation state control unit 33 may control the terrestrial base stations 111, 121 to other operation states in addition to or instead of the communication enabled state and the communication suspended state. For example, the terrestrial base station operation state control unit 33 may control the terrestrial base stations 111, 121 not only to be able to communicate with the communication devices 2 within the NTN surrounding terrestrial communication cells 112, 122, but also to be in an operation state such as a communication enhanced state in which communication resources are enhanced more than usual when there are a large number of communication devices 2 or when the service quality requirements for the communication devices 2 are high, or a communication restricted state in which communication with the communication devices 2 is completely suspended but communication resources are restricted or reduced more than usual.

[0039] The terrestrial base station operation status control unit 33 is provided together with the terrestrial communication cell detection unit 32 in the gateway 133 as a terrestrial station, and controls the operation status of each of the terrestrial base stations 111, 121 through inter-station interface IFs such as the X2 interface and Xn interface between the gateway 133 and each of the terrestrial base stations 111, 121.

[0040] Next, specific and exemplary control modes by the terrestrial base station operational status control unit 33 will be described individually for each type of information detected by the communication device detection unit 31. However, the terrestrial base station operational status control unit 33 in an actual wireless communication system 1 can arbitrarily combine these control modes.

[0041] In the first control mode, when the communication device detection unit 31 detects a communication device 2 (e.g., 2E to 2H) within the satellite communication cell 132, the communication available state switching unit 331 sets the operating state of the terrestrial base stations 111, 121 that can provide the NTN surrounding terrestrial communication cells 112, 122 to a communication available state, and when the communication device detection unit 31 does not detect a communication device 2 within the satellite communication cell 132, the communication inactive state switching unit 332 sets the operating state of the terrestrial base stations 111, 121 that can provide the NTN surrounding terrestrial communication cells 112, 122 to a communication inactive state.

[0042] For example, when the random access information detection unit 311 detects a preamble (random access information) transmitted by a communication device 2 in the satellite communication cell 132 to the communication satellite 131 (or when the communication device detection unit 31 detects a communication device 2 that has completed the random access procedure and is connected to the communication satellite 131), the terrestrial base stations 111, 121 that are switched to a communication-enabled state by the communication-enabled state switching unit 331 start or resume providing the NTN-periphery terrestrial communication cells 112, 122. At this time, the communication satellite 131 may intentionally not return a response (random access response) to the preamble transmitted from a communication device 2H in the overlapping area of ​​the satellite communication cell 132 and the NTN-periphery terrestrial communication cells 112, 122 (the entire NTN-periphery terrestrial communication cells 112, 122 in the example of FIG. 2), thereby inducing the communication device 2H to start a random access procedure with the newly activated terrestrial base stations 111, 121.

[0043] Note that the communication available state switching unit 331 may selectively set only the NTN-periphery terrestrial communication cells 112, 122 that overlap in whole or in part with the satellite communication cell 132 to a communication available state, instead of setting all of the NTN-periphery terrestrial communication cells 112, 122 to a communication available state (other NTN-periphery terrestrial communication cells 112, 122 outside the satellite communication cell 132, etc., are maintained in a communication suspended state, for example). In this case, high-quality communication services can be provided by the NTN-periphery terrestrial communication cells 112, 122 to the communication device 2 inside the satellite communication cell 132. Conversely, only the NTN-periphery terrestrial communication cells 112, 122 that do not overlap with the satellite communication cell 132 (that are completely outside the satellite communication cell 132) may be selectively set to a communication available state. In this case, while communication services by the communication satellite 131 are provided inside the satellite communication cell 132, the NTN-periphery terrestrial communication cells 112, 122 can be started up in advance in case the communication device 2 goes outside the satellite communication cell 132. Here, the terrestrial base station operation status control unit 33 can determine whether the satellite communication cell 132 overlaps with each NTN surrounding terrestrial communication cell 112, 122 based on the coverage area of ​​each NTN surrounding terrestrial communication cell 112, 122 acquired by the terrestrial communication cell detection unit 32.

[0044] On the other hand, if the random access information detection unit 311 does not detect the preamble transmitted by the communication device 2 in the satellite communication cell 132 to the communication satellite 131 (or if the communication device detection unit 31 does not detect the communication device 2 that has completed the random access procedure and is connected to the communication satellite 131), the terrestrial base stations 111, 121 that are switched to the communication suspension state by the communication suspension state switching unit 332 suspend their provision of the NTN-periphery terrestrial communication cells 112, 122. In this way, in a situation where it is considered that there is no communication device 2 in the satellite communication cell 132, it is considered that there is no communication device 2 connected to the terrestrial base stations 111, 121 in the NTN-periphery terrestrial communication cells 112, 122, and therefore power waste can be reduced by switching the terrestrial base stations 111, 121 to the communication suspension state. In addition, instead of placing all NTN-periphery terrestrial communication cells 112, 122 in a communication-suspended state, the communication-suspended state switching unit 332 may selectively place only the NTN-periphery terrestrial communication cells 112, 122 that overlap in whole or in part with the satellite communication cell 132 in a communication-suspended state (other NTN-periphery terrestrial communication cells 112, 122 outside the satellite communication cell 132, etc., are maintained in a communication-enabled state, for example).

[0045] Furthermore, the communication suspension state switching unit 332 may set the operation state of the terrestrial base stations 111, 121 to a communication suspension state when the random access information detection unit 311 does not detect a communication device 2 in the satellite communication cell 132 for a predetermined time. Furthermore, only the terrestrial base stations 111, 121 that can provide the NTN-periphery terrestrial communication cells 112, 122 that overlap with the satellite communication cell 132 may be switched to a communication suspension state by the communication suspension state switching unit 332 (the terrestrial base stations 111, 121 that provide the NTN-periphery terrestrial communication cells 112, 122 that do not overlap with the satellite communication cell 132 (that are completely outside the satellite communication cell 132) cannot be switched to a communication suspension state). When such a terrestrial base station 111, 121 is switched to a communication suspension state, even if a communication device 2 connected to the terrestrial base station 111, 121 is lost, the communication device 2 can be reconnected to the communication satellite 131, so that minimum services can be continuously provided to the communication device 2.

[0046] Furthermore, when the communication device detection unit 31 detects a communication device 2 in the location registration area to which the satellite communication cell 132 belongs (specifically, when there is a communication device 2 whose TAC for the location registration area is registered in the HLR), the terrestrial base stations 111, 121 switched to a communication available state by the communication available state switching unit 331 may start or resume providing the NTN-periphery terrestrial communication cells 112, 122. Similarly, when the communication device detection unit 31 does not detect a communication device 2 in the location registration area to which the satellite communication cell 132 belongs (specifically, when there is no communication device 2 whose TAC for the location registration area is registered in the HLR), the terrestrial base stations 111, 121 switched to a communication suspended state by the communication suspended state switching unit 332 suspends providing the NTN-periphery terrestrial communication cells 112, 122.

[0047] In this way, in a situation where it is considered that there are no communication devices 2 within the location registration area to which the satellite communication cell 132 belongs, it is considered that there are no communication devices 2 connected to the terrestrial base stations 111, 121 within the NTN-periphery terrestrial communication cells 112, 122, either, so power waste can be reduced by switching the terrestrial base stations 111, 121 to a communication pause state. Note that the communication pause state switching unit 332 may set the operation state of the terrestrial base stations 111, 121 to a communication pause state when the communication device detection unit 31 does not detect a communication device 2 within the location registration area for a predetermined period of time. Furthermore, it may be possible to have the communication pause state switchable by the communication pause state switching unit 332 only for the terrestrial base stations 111, 121 that can provide the NTN-periphery terrestrial communication cells 112, 122 that overlap with the satellite communication cell 132.

[0048] In the second control mode, when the communication device movement detection unit 312 detects a communication device 2 (e.g., 2F) moving toward the NTN-periphery ground communication cell 112, 122, the communication available state switching unit 331 sets the operating state of the terrestrial base station 111, 121 that can provide the NTN-periphery ground communication cell 112, 122 to a communication available state, and when the communication device movement detection unit 312 does not detect a communication device 2 moving toward the NTN-periphery ground communication cell 112, 122, the communication inactive state switching unit 332 sets the operating state of the terrestrial base station 111, 121 that can provide the NTN-periphery ground communication cell 112, 122 to a communication inactive state.

[0049] In this way, in a situation where there is no communication device 2 (e.g., 2H) within the NTN-periphery terrestrial communication cell 112, 122 and there is no communication device 2 (e.g., 2F) moving toward the NTN-periphery terrestrial communication cell 112, 122, it is considered that no communication device 2 connecting to the terrestrial base station 111, 121 will appear for the time being within the NTN-periphery terrestrial communication cell 112, 122, and therefore power waste can be reduced by switching the terrestrial base stations 111, 121 to a communication pause state. Note that, as with the other control modes described above, only the terrestrial base stations 111, 121 that can provide the NTN-periphery terrestrial communication cells 112, 122 that overlap with the satellite communication cell 132 may be made switchable to a communication pause state by the communication pause state switching unit 332.

[0050] In the third control mode, when the communication device position detection unit 313 detects a communication device 2 (e.g., 2G) located within a predetermined distance range 112', 122' from the NTN-periphery terrestrial communication cell 112, 122, the communication available state switching unit 331 sets the operating state of the terrestrial base station 111, 121 that can provide the NTN-periphery terrestrial communication cell 112, 122 to a communication available state, and when the communication device position detection unit 313 does not detect a communication device 2 located within a predetermined distance range 112', 122' from the NTN-periphery terrestrial communication cell 112, 122, the communication inactive state switching unit 332 sets the operating state of the terrestrial base station 111, 121 that can provide the NTN-periphery terrestrial communication cell 112, 122 to a communication inactive state.

[0051] In this way, in a situation where there is no communication device 2 (e.g., 2H) within the NTN-periphery terrestrial communication cell 112, 122, and there is also no communication device 2 (e.g., 2G) located within the predetermined distance range 112′, 122′ from the NTN-periphery terrestrial communication cell 112, 122, it is considered that no communication device 2 connecting to the terrestrial base station 111, 121 will appear in the NTN-periphery terrestrial communication cell 112, 122 for the time being, and therefore power waste can be reduced by switching the terrestrial base station 111, 121 to a communication pause state. Note that, as with the other control modes described above, the communication pause state switching unit 332 may set the operation state of the terrestrial base station 111, 121 to a communication pause state when the communication device position detection unit 313 does not detect a communication device 2 located within the predetermined distance range 112′, 122′ from the NTN-periphery terrestrial communication cell 112, 122 for a predetermined time. Furthermore, only the terrestrial base stations 111, 121 that can provide the NTN surrounding terrestrial communication cells 112, 122 that overlap with the satellite communication cell 132 may be made switchable to a communication suspension state by the communication suspension state switching unit 332.

[0052] In a fourth control mode, when the communication satellite 131 cannot satisfy the service quality requirement of a communication device 2 (e.g., 2H) in the satellite communication cell 132 detected by the service quality requirement detection unit 314, the communication available state switching unit 331 sets the operating state of the terrestrial base station 111, 121 that can provide the NTN-periphery terrestrial communication cell 112, 122 to the communication device 2 to a communication available state. For example, when the communication device 2H connected to the communication satellite 131 in the overlapping area of ​​the satellite communication cell 132 and the NTN-periphery terrestrial communication cell 112, 122 performs emergency communication such as an emergency call, or prioritized communication with high QoS requirements such as VoLTE in 4G or VoNR in 5G, and the communication satellite 131 cannot satisfy the QoS requirement, the terrestrial base station 111, 121 that provides the NTN-periphery terrestrial communication cell 112, 122 is controlled to an operating state that allows communication with the communication device 2H. Conversely, the NTN surrounding terrestrial communication cells 112, 122 in the overlapping area with the satellite communication cell 132 can be maintained in a communication pause state if the communication satellite 131 can satisfy the QoS requirements of the communication device 2H, thereby reducing power waste in the terrestrial base stations 111, 121.

[0053] The present disclosure has been described above based on the embodiments. The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of the respective components and treatment processes, and that such modifications are also within the scope of the present disclosure.

[0054] The functional configuration of each device 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 other LSIs. Examples of software resources include operating systems, applications, and other programs.

[0055] This disclosure may be expressed in the following terms:

[0056] Item 1: a communication device detection unit that detects a communication device within a non-terrestrial communication cell provided to the ground by the flying non-terrestrial base station; a terrestrial communication cell detection unit that detects terrestrial communication cells that can be provided on the ground by a terrestrial base station installed on the ground; a terrestrial base station operation state control unit that controls the operation state of the terrestrial base station based on the detection results of the communication device detection unit and the terrestrial communication cell detection unit; A communication control device comprising: Item 2: Item 1. The communication control device according to item 1, wherein the communication device detection unit detects the communication device based on random access information transmitted by the communication device to the non-terrestrial base station. Item 3: the terrestrial communication cell detection unit and the terrestrial base station operation state control unit are provided in a terrestrial station that is installed on the ground and is capable of communicating with the non-terrestrial base station, the terrestrial communication cell detection unit acquires information about the terrestrial communication cell from the terrestrial base station through an inter-station interface between the terrestrial station and the terrestrial base station; the terrestrial base station operation state control unit controls the operation state of the terrestrial base station through the inter-station interface; 3. The communication control device according to item 1 or 2. Item 4: the communication device detection unit detects the position of a communication device within the non-terrestrial communication cell; the terrestrial base station operation state control unit sets the operation state of the terrestrial base station to a communication enabled state in which communication with the communication device is possible when the position of the communication device is within a predetermined distance range from the terrestrial communication cell. 4. A communication control device according to any one of items 1 to 3. Item 5: the communication device detection unit detects the position of a communication device within the non-terrestrial communication cell; the terrestrial base station operation state control unit, when the position of the communication device is outside a predetermined distance range from the terrestrial communication cell, sets the operation state of the terrestrial base station to a communication suspension state in which communication with the communication device is not possible; 5. A communication control device according to any one of items 1 to 4. Item 6: the communication device detection unit detects movement of a communication device within the non-terrestrial communication cell; the terrestrial base station operation state control unit, when the communication device is moving toward the terrestrial communication cell, sets the operation state of the terrestrial base station to a communication enabled state in which communication with the communication device is possible; 6. A communication control device according to any one of items 1 to 5. Item 7: the communication device detection unit detects movement of a communication device within the non-terrestrial communication cell; the terrestrial base station operation state control unit, when the communication device is not moving toward the terrestrial communication cell, sets the operation state of the terrestrial base station to a communication suspension state in which communication with the communication device is not possible; 7. A communication control device according to any one of items 1 to 6. Item 8: the communication device detection unit detects quality of service requirements of communication devices within the non-terrestrial communication cell; the terrestrial base station operation state control unit, when the non-terrestrial base station cannot satisfy the service quality requirement, sets the operation state of the terrestrial base station that can provide a terrestrial communication cell to the communication device to a communication enabled state that allows communication with the communication device. 8. A communication control device according to any one of items 1 to 7. Item 9: 9. The communication control device according to any one of items 1 to 8, wherein the terrestrial base station operation state control unit sets the operation state of the terrestrial base station to a communication suspension state when the communication device detection unit does not detect a communication device within the non-terrestrial communication cell. Item 10: 10. The communication control device according to any one of items 1 to 9, wherein the terrestrial base station operation status control unit sets the operation status of the terrestrial base station to a communication suspension state when the communication device detection unit does not detect a communication device within a location registration area to which the non-terrestrial communication cell belongs. Item 11: 11. The communication control device according to any one of items 1 to 10, wherein the terrestrial base station operation state control unit sets the operation state of the terrestrial base station to a communication suspension state when the communication device detection unit does not detect a communication device in the non-terrestrial communication cell for a predetermined time. Item 12: 12. The communication control device according to any one of items 1 to 11, wherein the terrestrial base station operation state control unit is capable of setting the operation state of a terrestrial base station that can provide a terrestrial communication cell that overlaps with the non-terrestrial communication cell to a communication suspension state. Item 13: 13. The communication control device according to any one of items 1 to 12, wherein the non-terrestrial base station is a communication satellite flying in outer space. Item 14: detecting a communicator within a non-terrestrial communication cell provided to the ground by the flying non-terrestrial base station; A terrestrial base station installed on the ground detects a terrestrial communication cell that can be provided on the ground; Controlling the operation state of the terrestrial base station based on the detection results of the communication device and the terrestrial communication cell; A communication control method comprising: Item 15: detecting a communicator within a non-terrestrial communication cell provided to the ground by the flying non-terrestrial base station; A terrestrial base station installed on the ground detects a terrestrial communication cell that can be provided on the ground; Controlling the operation state of the terrestrial base station based on the detection results of the communication device and the terrestrial communication cell; A storage medium that stores a communication control program that causes a computer to execute the above. [Explanation of symbols]

[0057] 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 communication device detection unit, 32 terrestrial communication cell detection unit, 33 terrestrial base station operation state 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, 311 random access information detection unit, 312 communication device movement detection unit, 313 communication device position detection unit, 314 service quality request detection unit, 331 communication available state switching unit, 332 communication pause state switching unit.

Claims

1. A communication device detection unit that detects communication devices within non-ground communication cells provided to the ground by a flying non-ground base station, A ground communication cell detection unit that detects ground communication cells that can be provided to the ground by a ground base station installed on the ground, Based on the detection results of the communication device detection unit and the ground communication cell detection unit, a ground base station operating state control unit controls the operating state of the ground base station, Equipped with, The ground base station operational status control unit is a communication control device that, when the communication device detection unit does not detect a communication device within the location registration area to which the non-ground communication cell belongs, sets the operational status of the ground base station providing the ground communication cell belonging to the location registration area to a communication suspension state.

2. The communication control device according to claim 1, wherein the communication device detection unit detects the communication device based on random access information transmitted by the communication device to the non-terrestrial base station.

3. The ground communication cell detection unit and the ground base station operating status control unit are installed in a ground station that is installed on the ground and capable of communicating with the non-ground base station. The ground communication cell detection unit acquires information about the ground communication cell from the ground base station through the inter-station interface between the ground station and the ground base station. The ground base station operational status control unit controls the operational status of the ground base station through the inter-station interface. The communication control device according to claim 1.

4. The aforementioned communication device detection unit detects the position of the communication device within the non-terrestrial communication cell, The ground base station operational status control unit shall, when the location of the communication device is within a predetermined distance range from the ground communication cell, set the operational status of the ground base station to a communication-enabled state in which communication with the communication device is possible. The communication control device according to claim 1.

5. The aforementioned communication device detection unit detects the position of the communication device within the non-terrestrial communication cell, The ground base station operational status control unit shall, if the location of the communication device is outside a predetermined distance range from the ground communication cell, set the operational status of the ground base station to a communication suspension state in which communication with the communication device is impossible. The communication control device according to claim 1.

6. The aforementioned communication device detection unit detects the movement of a communication device within the non-terrestrial communication cell, The ground base station operational status control unit, when the communication device is moving toward the ground communication cell, sets the operational status of the ground base station to a communication-enabled state in which it can communicate with the communication device. The communication control device according to claim 1.

7. The aforementioned communication device detection unit detects the movement of a communication device within the non-terrestrial communication cell, The ground base station operational status control unit shall, if the communication device is not moving toward the ground communication cell, set the operational status of the ground base station to a communication suspension state in which communication with the communication device is impossible. The communication control device according to claim 1.

8. The communication device detection unit detects the service quality requirements of the communication devices within the non-terrestrial communication cell. If the non-terrestrial base station fails to meet the service quality requirements, the ground base station operational status control unit sets the operational status of a ground base station capable of providing a terrestrial communication cell to the communication device to a communication-enabled state in which it can communicate with the communication device. The communication control device according to claim 1.

9. The communication control device according to claim 1, wherein the ground base station operating state control unit sets the operating state of the ground base station to a communication pause state if the communication device detection unit does not detect a communication device within the non-ground communication cell.

10. The communication control device according to claim 1, wherein the ground base station operational status control unit sets the operational status of the ground base station to a communication suspension state if the communication device in the non-ground communication cell is not detected by the communication device detection unit for a predetermined period of time.

11. The communication control device according to claim 1, wherein the ground base station operational status control unit can set the operational status of a ground base station capable of providing a ground communication cell that overlaps with the non-ground communication cell to a communication suspension state.

12. The communication control device according to claim 1, wherein the non-terrestrial base station is a communications satellite orbiting in outer space.

13. Detecting communication devices within non-terrestrial communication cells provided to the ground by flying non-terrestrial base stations, The ground base station installed on the ground detects the ground communication cells that can be provided to the ground, Based on the detection results of the aforementioned communication device and the aforementioned ground communication cell, the operating status of the ground base station is controlled. Equipped with, A communication control method for controlling the operating state of the ground base station is to set the operating state of the ground base station providing the ground communication cell belonging to the location registration area to a communication suspension state when no communication device is detected within the location registration area to which the non-ground communication cell belongs.

14. Detecting communication devices within non-terrestrial communication cells provided to the ground by flying non-terrestrial base stations, The ground base station installed on the ground detects the ground communication cells that can be provided to the ground, Based on the detection results of the aforementioned communication device and the aforementioned ground communication cell, the operating status of the ground base station is controlled. Have the computer run it, Controlling the operating state of the ground base station involves a storage medium that stores a communication control program that, when no communication device is detected within the location registration area to which the non-ground communication cell belongs, sets the operating state of the ground base station providing the ground communication cell belonging to the location registration area to a communication suspension state.

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