Communication system, mobile unit, base station, and program

Abstract

A communication system including a mobile object and a first base station, a mobile object, a base station, and a program are provided. [Solution] In a system 10 including a mobile body 100 and a base station, the mobile body and the base station perform mobile communication such that the product of the antenna gain of the communication antenna on the transmitting side and the antenna gain of the communication antenna on the receiving side in mobile communication between the mobile body and the base station 200 using radio waves with a terahertz band frequency is proportional to the square of the cosecant of the elevation and depression angle in the propagation direction of the radio waves. The mobile body includes a communication antenna used for mobile communication between the mobile body and the base station 300, and a communication unit that performs mobile communication with the base station using a communication antenna 150 included in the mobile body such that the product of the antenna gain of the communication antenna on the transmitting side and the antenna gain of the communication antenna on the receiving side in mobile communication between the mobile body and the base station 200 using radio waves with a terahertz band frequency is proportional to the square of the cosecant of the elevation and depression angle in the propagation direction of the radio waves.

Description

[Technical field]

[0001] The present invention relates to a communication system, a mobile unit, a base station, and a program. [Background technology]

[0002] Patent Document 1 describes a P-MPFWA system equipped with a base station antenna that can expand the communication area in the elevation direction by significantly improving the area coverage compared to the conventional system while minimizing the decrease in maximum gain in the horizontal direction. [Prior art document] [Patent documents] [Patent Document 1] Patent No. 3761821 Summary of the Invention [Means for solving the problem]

[0003] According to an embodiment of the present invention, there is provided a communication system. The communication system may include a mobile object. The communication system may include a first base station. The mobile object and the first base station may perform mobile communication between the mobile object and the first base station using radio waves of a terahertz band frequency such that a product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile object and the first base station is proportional to a square of a cosecant of an elevation / depression angle in a propagation direction of the radio waves.

[0004] In the communication system, the radio wave reception power (P RE ) may satisfy the following formula:

[0005]

number

[0006] Here, P TR is the transmission power of the radio wave, and G TR is the antenna gain of the communication antenna at the transmitting side, and G REis the antenna gain of the communication antenna on the receiving side, λ is the wavelength of the radio wave, h is the altitude difference between the altitude of the communication antenna on the transmitting side and the altitude of the communication antenna on the receiving side, and θ is the elevation / depression angle.

[0007] In any of the above communication systems, the mobile body may have a first communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angles, and the first base station may have a second communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angles.

[0008] In any of the above communication systems, the mobile object may have a first communication antenna whose antenna gain is omnidirectional with respect to the elevation and depression angles, and the first base station may have a second communication antenna whose antenna gain is proportional to the square of the cosecant of the elevation and depression angles.

[0009] In any of the communication systems described above, the mobile device may perform mobile communication with a second base station having a coverage area that includes the coverage area of ​​the first base station, using radio waves at a frequency lower than the terahertz band, receive first presence information from the second base station indicating that the first base station is present within the coverage area of ​​the second base station, and perform mobile communication with the first base station based on the first presence information.

[0010] Any of the communication systems may further include an alarm device that is located outside the coverage area of ​​the first base station and may transmit second presence information to the mobile body using radio waves with a terahertz band frequency, indicating that the first base station is present within a predetermined range from the alarm device, and the mobile body may perform mobile communication with the first base station based on the second presence information.

[0011] According to one embodiment of the present invention, a mobile body is provided. The mobile body may include a communication antenna used for mobile communication between the mobile body and a base station. The mobile body may include a communication unit that performs mobile communication with the base station using the communication antenna included in the mobile body such that the product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile body and the base station using radio waves with a frequency in the terahertz band is proportional to the square of the cosecant of the elevation / depression angle in the propagation direction of the radio waves.

[0012] In the moving body, an antenna gain of the communication antenna included in the moving body may be proportional to the first power of the cosecant of the elevation / depression angle.

[0013] According to one embodiment of the present invention, there is provided a program that, when executed by a computer, causes the computer to function as any one of the mobile objects described above.

[0014] According to one embodiment of the present invention, there is provided a base station. The base station may include a communication antenna used for mobile communication between a mobile object and the base station. The base station may include a communication unit that performs mobile communication with the mobile object using the communication antenna included in the base station such that the product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile object and the base station using radio waves of a terahertz band frequency is proportional to the square of the cosecant of the elevation / depression angle in the propagation direction of the radio waves.

[0015] In the base station, an antenna gain of the communication antenna included in the base station may be proportional to the first power of the cosecant of the elevation / depression angle.

[0016] According to one embodiment of the present invention, there is provided a program for causing a computer to function as any one of the base stations when executed by the computer.

[0017] The above summary of the invention does not list all of the necessary features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0018] [Figure 1] An example of a system 10 is shown diagrammatically. [Diagram 2] FIG. 2 is an explanatory diagram for explaining propagation characteristics of radio waves. [Diagram 3] FIG. 2 is an explanatory diagram for explaining an antenna gain of a communication antenna. [Figure 4] 1 is an explanatory diagram for explaining an example of a communication state of a moving object 100. FIG. [Diagram 5] FIG. 11 is an explanatory diagram for explaining another example of the communication state of the moving object 100. [Figure 6] FIG. 11 is an explanatory diagram for explaining another example of the communication state of the moving object 100. [Figure 7] Another example of the system 10 is shown diagrammatically. [Figure 8] FIG. 2 is an explanatory diagram for explaining an example of an installation position of a communication antenna 150. [Figure 9] 2 illustrates an example of a functional configuration of a moving object 100. [Figure 10] 2 illustrates an example of a functional configuration of a base station 200. [Figure 11] FIG. 2 is an explanatory diagram for explaining an example of a processing flow of the system 10. [Figure 12] An example of the hardware configuration of a computer 1200 functioning as a mobile station 100 or a base station 200 is shown in schematic form. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] In the future, due to the spread of connected cars and smart trains, it is predicted that the amount of wireless communication traffic generated on roads and railways will increase. Since the current network capacity cannot accommodate these traffic demands, it is necessary to build coverage areas for roads and railways. In order to build the coverage area, it is possible to use broadband communication using high-frequency radio waves in the millimeter wave band or terahertz band, which are easy to secure communication capacity. However, it is difficult to extend the communication distance of radio waves in the millimeter wave band or terahertz band, which have large propagation attenuation. According to the system of this embodiment, for example, a mechanism is adopted in which a mobile body and a base station perform mobile communication so that the product of the antenna gain of the communication antenna on the transmitting side and the antenna gain of the communication antenna on the receiving side is proportional to the square of the cosecant of the elevation and depression angle in the propagation direction of radio waves with a frequency in the terahertz band.

[0020] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0021] 1 illustrates a schematic diagram of an example of a system 10. The system 10 may include a mobile unit 100 and a base station 200. The system 10 may further include a base station 300. The system 10 may be an example of a communication system.

[0022] The mobile object 100 may be any mobile object having a mobile communication function. The mobile object 100 is, for example, a vehicle. The vehicle is, for example, an automobile. The vehicle is, for example, a motorcycle. The vehicle may be a railroad car. The railroad car is, for example, a train. The train is, for example, a Shinkansen. FIG. 1 illustrates an example in which the mobile object 100 is an automobile.

[0023] The mobile object 100 performs mobile communication with, for example, the base station 200. The mobile object 100 performs mobile communication with the base station 200 using, for example, radio waves with a frequency in the terahertz band. The frequency in the terahertz band may be a frequency in a band between about 100 GHz and about 10 THz. The mobile object 100 may access the network 20 via the base station 200.

[0024] The network 20 includes, for example, a core network provided by a telecommunications carrier. The core network is compliant with, for example, a 5G (5th Generation) communication system. The core network may be compliant with a 6G (6th Generation) communication system or a communication system after the 6G (6th Generation) communication system. The core network may be compliant with a 3G (3rd Generation) communication system or an LTE (Long Term Evolution) communication system. The network 20 may include the Internet.

[0025] The mobile body 100 and the base station 200 perform mobile communication such that the product of the antenna gain of the communication antenna on the transmitting side and the antenna gain of the communication antenna on the receiving side in mobile communication between the mobile body 100 and the base station 200 using radio waves with a frequency in the terahertz band is proportional to the square of the cosecant of the elevation and depression angles in the propagation direction of the radio waves. For example, if the mobile body 100 has a communication antenna 150 whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angles, and the base station 200 has a communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angles, the product of the antenna gain of the communication antenna on the transmitting side and the antenna gain of the communication antenna on the receiving side in the mobile communication is proportional to the square of the cosecant of the elevation and depression angles in the propagation direction of the radio waves. Also, for example, if the mobile unit 100 has a communication antenna 150 whose antenna gain is non-directional with respect to the elevation and depression angles, and the base station 200 has a communication antenna whose antenna gain is proportional to the square of the cosecant of the elevation and depression angles, the product of the antenna gain of the communication antenna on the transmitting side and the antenna gain of the communication antenna on the receiving side in the mobile communication is proportional to the square of the cosecant of the elevation and depression angles in the propagation direction of the radio waves. The base station 200 may be an example of a first base station.

[0026] The base station 200 forms the coverage area 220 using, for example, a communication antenna. The base station 200 forms the coverage area 220 along, for example, a road. The road includes, for example, a national highway. The national highway includes, for example, a national expressway. The national highway may include a general national highway. The road includes, for example, a prefectural road. The road may include a municipal road. The base station 200 forms the coverage area 220 along, for example, a railroad track. The railroad track is, for example, a railroad track for railway vehicles. The railroad track is, for example, a railroad track for electric trains. The railroad track is, for example, a railroad track for Shinkansen trains. The base station 200 may form a linear coverage area 220.

[0027] The base station 200 is installed, for example, on a sign. The base station 200 is installed, for example, on a traffic light. When the base station 200 is installed on a sign or a traffic light, the base station 200 is installed at an altitude of about 5 m or more. The base station 200 is installed, for example, on a signboard. The base station 200 is installed, for example, on a utility pole. The base station 200 may be installed in any other location. FIG. 1 illustrates an example in which the base station 200 is installed on a sign 50.

[0028] The base station 200 is installed, for example, along a road or may be installed along a railroad track.

[0029] For example, two adjacent base stations 200 are installed so that at least a part of their coverage areas overlap each other. Two adjacent base stations 200 may also be installed so that their coverage areas do not overlap each other.

[0030] The mobile body 100 performs mobile communication with, for example, the base station 300. The mobile body 100 performs mobile communication with the base station 300, for example, using radio waves with a frequency lower than the terahertz band. The mobile body 100 performs mobile communication with the base station 300, for example, using radio waves with an anchor band frequency. The mobile body 100 performs mobile communication with the base station 300, for example, using radio waves with a frequency in the 2.1 GHz band. The mobile body 100 may access the network 20 via the base station 300.

[0031] For example, the mobile unit 100 performs mobile communication with the base station 300 before performing mobile communication with the base station 200. For example, the mobile unit 100 establishes mobile communication with the base station 300 when the mobile unit 100 is located outside the coverage area 220 of the base station 200 and inside the coverage area 320 of the base station 300.

[0032] The mobile unit 100 may perform mobile communication with the base station 300 using a communication antenna different from the communication antenna 150. Therefore, the mobile unit 100 may have two communication antennas: the communication antenna 150 for performing mobile communication with the base station 200, and the communication antenna for performing mobile communication with the base station 300.

[0033] The base station 300 forms a coverage area 320 using, for example, a communication antenna. The base station 300 forms, for example, a coverage area 320 that is wider than the coverage area 220 of the base station 200. The base station 300 forms, for example, a coverage area 320 that includes the coverage area 220 of the base station 200. The base station 300 may be an example of a second base station.

[0034] For example, the base station 300 executes a setting process for the mobile unit 100 to start data communication at the timing of establishing mobile communication with the mobile unit 100. For example, the base station 300 executes a subscriber authentication process for authenticating subscriber information of the mobile unit 100. For example, the base station 300 executes an assignment process for assigning an IP (Internet Protocol) address to the mobile unit 100. The base station 300 may execute any other process.

[0035] For example, after establishing mobile communication with the mobile unit 100, the base station 300 transmits presence information indicating that the base station 200 exists within the coverage area 320 of the base station 300. The presence information includes, for example, communication antenna information indicating communication antennas that the base station 200 has.

[0036] The mobile unit 100 may receive presence information from the base station 300 and perform mobile communication with the base station 200 based on the received presence information. For example, in order to establish mobile communication with the base station 200, the mobile unit 100 sets the communication antenna 150 to a state in which radio waves can be received.

[0037] For example, when the mobile body 100 is located at a position that is within the coverage area 220 of the base station 200 and within the coverage area 320 of the base station 300, the mobile body 100 performs data communication using both the mobile communication between the mobile body 100 and the base station 200 and the mobile communication between the mobile body 100 and the base station 300. The mobile body 100 performs the data communication using, for example, a carrier aggregation protocol. When the mobile body 100 is located at a position that is within the coverage area 220 of the base station 200 and within the coverage area 320 of the base station 300, the mobile body 100 may perform data communication using only the mobile communication between the mobile body 100 and the base station 200.

[0038] In the future, it is conceivable to use broadband communication using high-frequency radio waves in the terahertz band to build coverage areas for roads and railroads where traffic volume is expected to increase. However, it is difficult to extend the communication distance of radio waves in the terahertz band, which have large propagation attenuation. In addition, the introduction of beamforming is conceivable to extend the communication distance of mobile communication using radio waves in the terahertz band. However, beamforming is not a technology that extends the coverage area itself, but a technology that extends the communication distance by making a beam that forms a communication spot follow a mobile body equipped with a mobile communication function. Therefore, in order to make the beam follow the mobile body with high accuracy, the base station must perform a huge amount of calculations, including matrix calculations, in accordance with the movement of the mobile body. In particular, when the mobile body is moving at high speed, such as when a car is running on a highway, the base station must perform the calculations at a higher speed. Therefore, when using beamforming to extend the communication distance of mobile communication using radio waves in the terahertz band, the base station must be equipped with hardware that meets high calculation processing requirements, and as a result, the base station becomes large and expensive.

[0039] In contrast, according to the system 10 of this embodiment, the mobile unit 100 and the base station 200 perform mobile communication such that the product of the antenna gain of the communication antenna on the transmitting side and the antenna gain of the communication antenna on the receiving side in the mobile communication between the mobile unit 100 and the base station 200 using radio waves of a terahertz frequency band is proportional to the square of the cosecant of the elevation / depression angle in the propagation direction of the radio waves. The system 10 of this embodiment is equipped with a cosecant directional antenna in the base station 200, and forms a coverage area 220 along roads and railroads using the cosecant directional antenna, thereby making it possible to extend the communication distance of the mobile communication using radio waves in the terahertz band beyond the communication distance of the conventional mobile communication using radio waves in the terahertz band without introducing beamforming. For example, the system 10 of this embodiment can extend the communication distance of the mobile communication using radio waves in the terahertz band to about 200 m. In addition, the system 10 according to the present embodiment performs mobile communication such that the product of the antenna gain of the communication antenna on the transmitting side and the antenna gain of the communication antenna on the receiving side is proportional to the square of the cosecant of the elevation / depression angle in the propagation direction of the radio waves, so that when the mobile body moves with the altitude of the communication antenna of the mobile body being constant, the reception power of the communication antenna on the receiving side can be made constant. As a result, the system 10 according to the present embodiment can further stabilize the communication quality of mobile communication using radio waves in the terahertz band. In addition, the system 10 according to the present embodiment can suppress the occurrence of radio wave interference between radio waves in one coverage area and radio waves in another coverage area when a coverage area is formed on each of adjacent lanes or railroads by forming a coverage area along a road or railroad. As described above, the system 10 according to the present embodiment can extend the communication distance of mobile communication using radio waves in the terahertz band and further stabilize the communication quality of the mobile communication by using a low-cost and small base station.

[0040] Furthermore, according to the system 10 of this embodiment, the mobile unit 100 performs mobile communication with the base station 300 having a coverage area 320 that includes the coverage area 220 of the base station 200. Then, the base station 300 executes a setting process for the mobile unit 100 to start data communication before the mobile unit 100 starts mobile communication with the base station 200. As a result, at the timing when the mobile unit 100 starts mobile communication with the base station 200, the setting process for the mobile unit 100 to start data communication has already been executed by the base station 300, so that the system 10 of this embodiment allows the mobile unit to start data communication using radio waves with a frequency in the terahertz band in a short time. Furthermore, when the mobile object 100 is located at a position that is within the coverage area 220 of the base station 200 and within the coverage area 320 of the base station 300, the mobile object 100 can perform data communication using both the mobile communication between the mobile object 100 and the base station 200 and the mobile communication between the mobile object 100 and the base station 300, so that the system 10 according to this embodiment can realize high-speed mobile data communication as a whole system. In addition, when the mobile object 100 moves from within the coverage area 220 of the base station 200 to outside the coverage area 220 of the base station 200, the mobile object 100 can continue data communication using the mobile communication between the mobile object 100 and the base station 300, so that the system 10 according to this embodiment can realize seamless mobile data communication as a whole system.

[0041] Fig. 2 is an explanatory diagram for explaining the propagation characteristics of radio waves. In the xy coordinate system shown in Fig. 2, the x-axis is the horizontal direction and the y-axis is the vertical direction.

[0042] The communication antenna 150 is (x v ,y v The communication antenna 250 of the base station 200 is located at (x b ,y b ) is located.

[0043] When the communication antenna 150 transmits radio waves and the communication antenna 250 receives the radio waves, the communication antenna 150 is the transmitting communication antenna and the communication antenna 150 is the receiving communication antenna. On the other hand, when the communication antenna 250 transmits radio waves and the communication antenna 150 receives the radio waves, the communication antenna 250 is the transmitting communication antenna and the communication antenna 150 is the receiving communication antenna. The propagation direction of the radio waves is assumed to be parallel to a straight line passing through the communication antennas 150 and 250.

[0044] r is the distance between the transmitting communication antenna and the receiving communication antenna. r satisfies the following formula:

[0045]

number

[0046] d is the distance in the x-axis direction between the transmitting communication antenna and the receiving communication antenna. d satisfies the following formula.

[0047]

number

[0048] h is the altitude difference between the altitude of the transmitting communication antenna and the altitude of the receiving communication antenna. h satisfies the following formula:

[0049]

number

[0050] θ is the elevation / depression angle in the propagation direction of the radio wave. When the communication antenna 150 is the transmitting side communication antenna and the communication antenna 250 is the receiving side communication antenna, θ is the elevation angle. On the other hand, when the communication antenna 250 is the transmitting side communication antenna and the communication antenna 150 is the receiving side communication antenna, θ is the depression angle.

[0051] Radio wave receiving power (PRE ) is calculated by the Friis propagation law shown below, TR In the Friis propagation formula shown below, G TR is the antenna gain of the transmitting communication antenna, and G RE is the antenna gain of the receiving communication antenna, and λ is the wavelength of the radio wave.

[0052]

number

[0053] Here, r = h × cosecθ is substituted into the Friis transmission formula shown above. In this case, P RE satisfies the following formula:

[0054]

number

[0055] As shown in the above formula, P RE is (1 / cosecθ) 2 Since it contains G TR ×G RE (cosecθ) 2 If proportional to P RE is constant regardless of d. Therefore, G TR ×G RE (cosecθ) 2 When the terahertz frequency is proportional to the terahertz wave frequency, the communication quality of mobile communication using terahertz wave can be further stabilized.

[0056] FIG. 3 is an explanatory diagram for explaining the antenna gain of a communication antenna. In FIG. 3, the antenna gain of the communication antenna is a gain threshold (G th ) is shown.

[0057] The upper part of Fig. 3 illustrates an example in which the antenna gain of communication antenna 150 is non-directional with respect to the elevation and depression angles, and the antenna gain of communication antenna 250 is proportional to the square of the cosecant of the elevation and depression angles. The lower part of Fig. 3 illustrates an example in which the antenna gain of communication antenna 150 is proportional to the first power of the cosecant of the elevation and depression angles, and the antenna gain of communication antenna 250 is proportional to the first power of the cosecant of the elevation and depression angles. As shown in Fig. 3, when the antenna gain of the communication antenna is G th The larger areas are communications antennas whose antenna gain is proportional to the square of the cosecant of the elevation / depression angles, followed by communications antennas whose antenna gain is proportional to the first power of the cosecant of the elevation / depression angles, and finally communications antennas whose antenna gain is omnidirectional with respect to the elevation / depression angles.

[0058] Here, the sizes of a communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation / depression angle and a communication antenna whose antenna gain is proportional to the square of the cosecant of the elevation / depression angle will be described. The size of a communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation / depression angle is smaller than the size of a communication antenna whose antenna gain is proportional to the square of the cosecant of the elevation / depression angle. The size of a communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation / depression angle is, for example, about 1 / 2 to 1 / 3 of the size of a communication antenna whose antenna gain is proportional to the square of the cosecant of the elevation / depression angle. The size of a communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation / depression angle is, for example, about 1 cm in the 300 GHz band. 3 ~4cm 3 It is.

[0059] As described above, the size of a communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angles is small. Therefore, when a communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angles is adopted as the communication antenna 150, the communication antenna 150 can be easily installed in a position where the wiring connected to the communication antenna 150 can be hidden or in a position where the visibility of the communication antenna 250 is good. Furthermore, when a communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angles is adopted as the communication antenna 250, the communication antenna 250 can be easily installed in a position where the base station 200 is not hindered from checking signs, traffic lights, etc. installed thereon. As a result, when communication antennas whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angles are adopted as the communication antennas 150 and 250, the degree of freedom of the installation position of the communication antennas can be further increased in the entire system.

[0060] 4 is an explanatory diagram for explaining an example of the communication state of the mobile object 100. Here, a state in which the mobile object 100 has not established mobile communication is taken as a starting state. It is assumed that the base station 202 installed on the sign 52 and the base station 204 installed on the sign 54 have the same functions as the base station 200, and that the moving direction of the mobile object 100 is from right to left.

[0061] 4 illustrates an example of a case where the mobile unit 100 moves from outside the coverage area 320 of the base station 300 to inside the coverage area 320 of the base station 300. In response to moving from outside the coverage area 320 of the base station 300 to inside the coverage area 320 of the base station 300, for example, the mobile unit 100 establishes mobile communication with the base station 300 using radio waves with a frequency lower than the terahertz band.

[0062] The base station 300 may execute a setting process for the mobile object 100 to start data communication at the timing of establishing mobile communication with the mobile object 100. In response to the completion of the setting process by the base station 300, the mobile object 100 may start data communication between the mobile object 100 and the base station 300 using the mobile communication.

[0063] 4 illustrates an example of a case where the mobile unit 100 moves from outside the coverage area 222 of the base station 202 to inside the coverage area 222 of the base station 202. In response to the mobile unit 100 moving from outside the coverage area 222 of the base station 202 to inside the coverage area 222 of the base station 202, for example, the mobile unit 100 establishes mobile communication with the base station 202 using radio waves with a terahertz frequency band. In response to the establishment of mobile communication with the base station 202, the mobile unit 100 may start data communication using both the mobile communication between the mobile unit 100 and the base station 202 and the mobile communication between the mobile unit 100 and the base station 300.

[0064] 5 is an explanatory diagram for explaining another example of the communication state of the mobile object 100. Here, differences from the explanation for FIG. 4 will be mainly explained.

[0065] 5 illustrates an example in which the mobile unit 100 is moving within the coverage area 222 of the base station 202. While the mobile unit 100 is located within the coverage area 222 of the base station 202, the mobile unit 100 may perform data communication using both the mobile communication between the mobile unit 100 and the base station 202 and the mobile communication between the mobile unit 100 and the base station 300.

[0066] For example, while the mobile object 100 is located within the coverage area 222 of the base station 202, the mobile object 100 transmits location information indicating the location of the mobile object 100 to the base station 300. Based on the location of the mobile object 100 indicated by the location information received from the mobile object 100, the base station 300 determines whether or not the mobile object 100 should perform handover (HO) from the base station 202 to the base station 204, the base station with which the mobile object 100 performs mobile communication using radio waves of a terahertz frequency band.

[0067] For example, when the mobile unit 100 is located within the coverage area 222 of the base station 202, and the distance from the mobile unit 100 to the base station 204 is shorter than a predetermined distance threshold, the base station 300 determines to perform a handover from the base station 202 to the base station 204. On the other hand, when the mobile unit 100 is located within the coverage area 222 of the base station 202, and the distance from the mobile unit 100 to the base station 204 is longer than the distance threshold, the base station 300 determines not to perform a handover from the base station 202 to the base station 204. Here, the explanation will be continued assuming that the base station 300 has determined to perform a handover from the base station 202 to the base station 204.

[0068] For example, in response to determining to hand over from base station 202 to base station 204, base station 300 transmits a handover instruction to mobile unit 100 to instruct the mobile unit 100 to hand over the base station with which mobile unit 100 performs mobile communication using radio waves in the terahertz band from base station 202 to base station 204. The handover instruction includes, for example, handover source information indicating the base station from which the handover originates. The handover instruction includes, for example, handover destination information indicating the base station to which the handover is to be performed.

[0069] In response to receiving the handover instruction from base station 300, mobile unit 100 may hand over the base station with which mobile unit 100 performs mobile communication using radio waves with terahertz band frequencies from base station 202 to base station 204. Here, the explanation will be continued assuming that mobile unit 100 has handed over the base station with which mobile unit 100 performs mobile communication using radio waves with terahertz band frequencies from base station 202 to base station 204.

[0070] 5 illustrates an example of a case where the mobile unit 100 moves from outside the coverage area 224 of the base station 204 to inside the coverage area 224 of the base station 204. In response to the mobile unit 100 moving from outside the coverage area 224 of the base station 204, which is the handover destination, to inside the coverage area 224 of the base station 204, the mobile unit 100 may start data communication using both the mobile communication between the mobile unit 100 and the base station 204 and the mobile communication between the mobile unit 100 and the base station 300.

[0071] Fig. 6 is an explanatory diagram for explaining another example of the communication state of the mobile object 100. Here, differences from the explanations for Fig. 4 and Fig. 5 will be mainly explained.

[0072] 6 illustrates an example of a case where the mobile unit 100 is moving within the coverage area 224 of the base station 204. While the mobile unit 100 is located within the coverage area 224 of the base station 204, the mobile unit 100 may perform data communication using both the mobile communication between the mobile unit 100 and the base station 204 and the mobile communication between the mobile unit 100 and the base station 300.

[0073] For example, while the mobile object 100 is located within the coverage area 224 of the base station 204, the mobile object 100 transmits location information to the base station 300. Based on the location of the mobile object 100 indicated by the location information received from the mobile object 100, the base station 300 determines whether or not the mobile object 100 should perform handover of the base station 204 with which the mobile object 100 performs mobile communication using radio waves in the terahertz band to another base station.

[0074] For example, when the mobile unit 100 is located within the coverage area 224 of the base station 204, if there is another base station whose distance from the mobile unit 100 is shorter than a predetermined distance threshold, the base station 300 determines to perform a handover from the base station 204 to the other base station. On the other hand, when the mobile unit 100 is located within the coverage area 224 of the base station 204, if there is no other base station whose distance from the mobile unit 100 is shorter than the distance threshold, the base station 300 determines not to perform a handover from the base station 204 to the other base station. Here, the explanation will be continued assuming that the base station 300 has determined not to perform a handover from the base station 204 to the other base station.

[0075] 6 illustrates an example of a case where the mobile unit 100 moves from within the coverage area 224 of the base station 204 to outside the coverage area 224 of the base station 204. In response to the mobile unit 100 moving from within the coverage area 224 of the base station 204 to outside the coverage area 224 of the base station 204, the mobile unit 100 may start data communication between the mobile unit 100 and the base station 300 using mobile communication.

[0076] According to the system 10 according to Figs. 4 to 6, when the mobile body 100 is located within the coverage area 320 of the base station 300, if the mobile body 100 is located within at least one of the coverage area 222 of the base station 202 and the coverage area 224 of the base station 204, the mobile body 100 performs data communication using both the mobile communication between the mobile body 100 and the base station 202 or the base station 204 and the mobile communication between the mobile body 100 and the base station 300. On the other hand, when the mobile body 100 is located within the coverage area 320 of the base station 300, if the mobile body 100 is not located within the coverage area 222 of the base station 202 or within the coverage area 224 of the base station 204, the mobile body 100 performs data communication using the mobile communication between the mobile body 100 and the base station 300. As a result, the system 10 according to Figs. 4 to 6 can realize high-speed and seamless mobile data communication as a whole system.

[0077] 7 is a schematic diagram of another example of the system 10. Here, differences from the system 10 shown in FIG. 1 will be mainly described.

[0078] The system 10 may further include a notification device 400. The notification device 400 notifies the mobile unit 100 that the base station 200 is located nearby.

[0079] The notification device 400 forms a coverage area 420 using, for example, a communication antenna. The notification device 400 forms the coverage area 420 along, for example, a road. The notification device 400 forms the coverage area 420 along, for example, a railroad track. The notification device 400 may form a linear coverage area 420.

[0080] The notification device 400 notifies the mobile body 100 that the base station 200 is nearby, for example, by transmitting presence information indicating that the base station 200 is present within a predetermined range from the notification device 400 to the mobile body 100. The presence information includes, for example, communication antenna information of the base station 200.

[0081] The alarm device 400 transmits the presence information to the moving object 100 using, for example, radio waves with a frequency in the terahertz band. The alarm device 400 may transmit the presence information to the moving object 100 using radio waves with a frequency lower than the terahertz band.

[0082] The mobile unit 100, for example, receives presence information from the notification device 400, and performs mobile communication with the base station 200 based on the received presence information. For example, in order to establish mobile communication with the base station 200, the mobile unit 100 sets the communication antenna 150 to a state in which radio waves can be received.

[0083] The notification device 400 may be connected to the network 20. The notification device 400 does not have to be connected to the network 20.

[0084] The notification device 400 is arranged, for example, outside the coverage area 220 of the base station 200. The notification device 400 is arranged, for example, outside the coverage area 320 of the base station 300.

[0085] According to the system 10 of FIG. 7, the mobile unit 100 changes the state of the communication antenna 150 to a state in which radio waves can be received in response to receiving the presence information from the notification device 400. As a result, the mobile unit 100 can change the state of the communication antenna 150 to a state in which radio waves can be received before moving from outside the coverage area 220 of the base station 200 to inside the coverage area 220 of the base station 200, so that the system 10 of FIG. 7 can establish mobile communication between the mobile unit and the base station using radio waves in the terahertz band at a higher speed. Furthermore, when the notification device 400 forms a coverage area 420 along a road or a railroad, the system 10 of FIG. 7 can prevent the notification device from notifying communication terminals and mobile units located around the road or railroad, and as a result, can prevent unnecessary power consumption by communication terminals and mobile units located around the road or railroad.

[0086] Fig. 8 is an explanatory diagram for explaining an example of the installation position of the communication antenna 150. Fig. 8 illustrates an example of the installation position of the communication antenna 150 when the moving body 100 is an automobile.

[0087] The communication antenna 150 is installed, for example, in a position where it is possible to hide the wiring connected to the communication antenna 150. The communication antenna 150 is installed, for example, in a position where it has a good view with respect to the communication antenna 250. The communication antenna 150 is installed, for example, in a position where it is possible to hide the wiring connected to the communication antenna 150 and also in a position where it has a good view with respect to the communication antenna 250.

[0088] 8, the communication antenna 150 is installed behind a rearview mirror or as a shark fin antenna. The communication antenna 150 may be installed in any other position of the mobile unit 100.

[0089] 9 illustrates an example of a functional configuration of the moving body 100. The moving body 100 includes a storage unit 102, a communication unit 104, a location information acquisition unit 106, a communication antenna 150, and a communication antenna 160. Note that it is not essential that the moving body 100 includes all of these components.

[0090] The storage unit 102 stores various types of information, for example, communication antenna information indicating communication antennas that the mobile object 100 has.

[0091] The communication unit 104 performs mobile communication with a base station. The communication unit 104 performs mobile communication with the base station 200, for example, using a communication antenna 150. The communication unit 104 performs mobile communication with the base station 200, for example, using the communication antenna 150, such that the product of the antenna gain of a communication antenna on the transmitting side and the antenna gain of a communication antenna on the receiving side in mobile communication between the mobile unit 100 and the base station 200 using radio waves with a frequency in the terahertz band is proportional to the square of the cosecant of the elevation / depression angle in the propagation direction of the radio waves.

[0092] For example, when establishing mobile communication with the base station 200, the communication unit 104 transmits an establishment request to the base station 200. The establishment request includes the communication antenna information stored in the storage unit 102, for example.

[0093] The communication unit 104 performs mobile communication with the base station 300 using, for example, the communication antenna 160. The communication unit 104 performs mobile communication with the base station 300 using, for example, radio waves with a frequency lower than the terahertz band. The communication unit 104 receives presence information from the base station 300, for example.

[0094] The communication unit 104 may perform wireless communication with the notification device 400. The communication unit 104 performs wireless communication with the notification device 400, for example, by using a communication antenna 150. The communication unit 104 may perform wireless communication with the notification device 400, by using a communication antenna 160. The communication unit 104 receives presence information from the notification device 400, for example.

[0095] The communication unit 104 performs mobile communication with the base station 200, for example, based on the presence information received from the base station 300 or the notification device 400. For example, in order to establish mobile communication with the base station 200, the mobile unit 100 sets the communication antenna 150 to a state in which radio waves can be received.

[0096] The communication unit 104 performs mobile communication with the base station 200, for example, based on the communication antenna information of the base station 200 included in the presence information received from the base station 300 or the alarm device 400. For example, when the antenna gain of the communication antenna 150 is proportional to the first power of the cosecant of the elevation and depression angle in the propagation direction of the radio wave, and the base station 200 has a communication antenna 250 whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angle in the propagation direction of the radio wave, the communication unit 104 sets the state of the communication antenna 150 to a state in which radio waves can be received. On the other hand, when the antenna gain of the communication antenna 150 is proportional to the first power of the cosecant of the elevation and depression angle in the propagation direction of the radio wave, and the base station 200 does not have a communication antenna 250 whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angle in the propagation direction of the radio wave, the communication unit 104 does not set the state of the communication antenna 150 to a state in which radio waves can be received.

[0097] For example, when the antenna gain of the communication antenna 150 is non-directional with respect to the elevation and depression angles in the propagation direction of the radio waves, and when the base station 200 has a communication antenna 250 whose antenna gain is proportional to the square of the cosecant of the elevation and depression angles in the propagation direction of the radio waves, the mobile unit 100 sets the state of the communication antenna 150 to a state in which radio waves can be received. On the other hand, when the antenna gain of the communication antenna 150 is non-directional with respect to the elevation and depression angles in the propagation direction of the radio waves, and when the base station 200 does not have a communication antenna 250 whose antenna gain is proportional to the square of the cosecant of the elevation and depression angles in the propagation direction of the radio waves, the mobile unit 100 does not set the state of the communication antenna 150 to a state in which radio waves can be received.

[0098] The location information acquisition unit 106 acquires location information of the moving object 100. The location information acquisition unit 106 acquires the location information by using, for example, a Global Navigation Satellite System (GNSS) function. The location information acquisition unit 106 acquires the location information by using, for example, a Global Positioning System (GPS) function. The location information acquisition unit 106 may acquire the location information by using a Real Time Kinematic (RTK) function.

[0099] The location information acquisition unit 106 acquires location information, for example, while the mobile object 100 is located within the coverage area 220 of the base station 200. The communication unit 104 may transmit the location information acquired while the mobile object 100 is located within the coverage area 220 of the base station 200 to the base station 300.

[0100] The communication unit 104 receives a handover instruction, for example, from the base station 300. In response to receiving the handover instruction from the base station 300, the communication unit 104 may hand over the base station with which the mobile unit 100 performs mobile communication using radio waves with a terahertz band frequency from the handover source base station to the handover destination base station.

[0101] 10 illustrates an example of a functional configuration of the base station 200. The base station 200 includes a communication antenna 252, a communication antenna 254, and a communication unit 256. It is not essential that the base station 200 includes all of these components.

[0102] The communication antenna 252 may have an antenna gain proportional to the first power of the cosecant of the elevation / depression angle in the propagation direction of radio waves of a terahertz frequency band. The communication antenna 254 may have an antenna gain proportional to the square of the cosecant of the elevation / depression angle in the propagation direction of radio waves of a terahertz frequency band.

[0103] The communication unit 256 performs mobile communication with the mobile body 100. The communication unit 256 performs mobile communication with the mobile body 100, for example, using the communication antenna 252. The communication unit 256 performs mobile communication with the mobile body 100, for example, using the communication antenna 254. The communication unit 256 performs mobile communication with the mobile body 100, for example, using the communication antenna 252 or the communication antenna 254, such that the product of the antenna gain of the communication antenna on the transmitting side and the antenna gain of the communication antenna on the receiving side in mobile communication between the mobile body 100 and the base station 200 using radio waves with a frequency in the terahertz band is proportional to the square of the cosecant of the elevation / depression angle in the propagation direction of the radio waves.

[0104] The communication unit 256 performs mobile communication with the mobile body 100 based on the communication antenna information of the mobile body 100 included in the establishment request received from the mobile body 100. For example, when the mobile body 100 has a communication antenna 150 whose antenna gain is proportional to the first power of the cosecant of the elevation and depression angles in the propagation direction of radio waves, the communication unit 256 performs mobile communication with the mobile body 100 using the communication antenna 252. For example, when the mobile body 100 has a communication antenna 150 whose antenna gain is non-directional with respect to the elevation and depression angles in the propagation direction of radio waves, the communication unit 256 performs mobile communication with the mobile body 100 using the communication antenna 254.

[0105] 11 is an explanatory diagram for explaining an example of the flow of processing in the system 10. Here, a state in which the mobile object 100 has not established mobile communication is taken as a starting state.

[0106] In step (step may be abbreviated as S) 102, in response to the mobile unit 100 moving from outside the coverage area 320 of the base station 300 into the coverage area 320 of the base station 300, the communication unit 104 establishes mobile communication with the base station 300 using the communication antenna 160. In S104, in response to the establishment of mobile communication with the mobile unit 100 in S102, the base station 300 transmits presence information to the mobile unit 100.

[0107] In S106, the communication unit 104 establishes mobile communication with the base station 200 using the communication antenna 150 based on the presence information received from the base station 300 in S104. In response to the mobile unit 100 moving from outside the coverage area 220 of the base station 200 to inside the coverage area 220 of the base station 200, the mobile unit 100 establishes mobile communication with the base station 200 using the communication antenna 150. In response to the establishment of mobile communication, the mobile unit 100 and the base station 200 start mobile communication such that the product of the antenna gain of the communication antenna on the transmitting side and the antenna gain of the communication antenna on the receiving side in mobile communication between the mobile unit 100 and the base station 200 using radio waves with a frequency in the terahertz band is proportional to the square of the cosecant of the elevation / depression angle in the propagation direction of the radio waves.

[0108] In S108, in response to establishing mobile communication with base station 200, communication unit 104 transmits to base station 300 the location information of mobile unit 100 acquired by location information acquisition unit 106. In S110, base station 300 determines whether or not to hand over the base station with which mobile unit 100 performs mobile communication using radio waves with a terahertz frequency band from base station 200 to another base station based on the location information received from mobile unit 100 in S108. Here, the explanation will be continued assuming that base station 300 has determined to hand over from base station 200 to another base station.

[0109] In S112, base station 300 transmits a handover command to mobile station 100. In S114, communication unit 104 hands over the base station performing mobile communication using radio waves with a terahertz frequency band from base station 200 to another base station based on the handover command received from base station 300 in S112. Thereafter, mobile communication between mobile station 100 and base station 200 ends.

[0110] 12 is a schematic diagram showing an example of a hardware configuration of a computer 1200 functioning as a mobile station 100 or a base station 200. A program installed in the computer 1200 can cause the computer 1200 to function as one or more "parts" of the apparatus according to the above embodiment, or cause the computer 1200 to execute operations or one or more "parts" associated with the apparatus according to the above embodiment, and / or cause the computer 1200 to execute a process or steps of the process according to the above embodiment. Such a program can be executed by the CPU 1212 to cause the computer 1200 to execute specific operations associated with some or all of the blocks of the flowcharts and block diagrams described herein.

[0111] The computer 1200 according to this embodiment includes a CPU 1212, a RAM 1214, and a graphics controller 1216, which are connected to each other by a host controller 1210. The computer 1200 also includes input / output units such as a communication interface 1222, a storage device 1224, a DVD drive 1226, and an IC card drive, which are connected to the host controller 1210 via an input / output controller 1220. The DVD drive 1226 may be a DVD-ROM drive, a DVD-RAM drive, or the like. The storage device 1224 may be a hard disk drive, a solid state drive, or the like. The computer 1200 also includes legacy input / output units such as a ROM 1230 and a keyboard 1242, which are connected to the input / output controller 1220 via an input / output chip 1240.

[0112] The CPU 1212 operates according to a program stored in the ROM 1230 and the RAM 1214, thereby controlling each unit. The graphic controller 1216 acquires image data generated by the CPU 1212 into a frame buffer or the like provided in the RAM 1214 or into itself, and causes the image data to be displayed on the display device 1218.

[0113] The communication interface 1222 communicates with other electronic devices via a network. The storage device 1224 stores programs and data used by the CPU 1212 in the computer 1200. The DVD drive 1226 reads programs or data from a DVD-ROM 1227 or the like and provides the programs or data to the storage device 1224. The IC card drive reads programs and data from an IC card and / or writes programs and data to an IC card.

[0114] The ROM 1230 stores therein a boot program or the like that is executed by the computer 1200 upon activation, and / or a program that depends on the hardware of the computer 1200. The input / output chip 1240 may also connect various input / output units to the input / output controller 1220 via a USB port, a parallel port, a serial port, a keyboard port, a mouse port, and the like.

[0115] The programs are provided by a computer-readable storage medium such as a DVD-ROM 1227 or an IC card. The programs are read from the computer-readable storage medium, installed in the storage device 1224, the RAM 1214, or the ROM 1230, which are also examples of computer-readable storage media, and executed by the CPU 1212. Information processing described in these programs is read by the computer 1200, and brings about cooperation between the programs and the various types of hardware resources described above. An apparatus or method may be constructed by implementing operations or processing of information according to the use of the computer 1200.

[0116] For example, when communication is performed between the computer 1200 and an external device, the CPU 1212 may execute a communication program loaded in the RAM 1214 and instruct the communication interface 1222 to perform communication processing based on the processing described in the communication program. Under the control of the CPU 1212, the communication interface 1222 reads transmission data stored in a transmission buffer area provided in the RAM 1214, the storage device 1224, the DVD-ROM 1227, or a recording medium such as an IC card, and transmits the read transmission data to a network, or writes reception data received from the network to a reception buffer area or the like provided on the recording medium.

[0117] Furthermore, the CPU 1212 may cause all or a necessary portion of a file or database stored in an external recording medium such as the storage device 1224, the DVD drive 1226 (DVD-ROM 1227), an IC card, etc. to be read into the RAM 1214, and perform various types of processing on the data on the RAM 1214. The CPU 1212 may then write back the processed data to the external recording medium.

[0118] Various types of information, such as various types of programs, data, tables, and databases, may be stored in the recording medium and undergo information processing. The CPU 1212 may perform various types of processing on the data read from the RAM 1214, including various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, information search / replacement, etc., as described throughout this disclosure and specified by the instruction sequence of the program, and write back the results to the RAM 1214. The CPU 1212 may also search for information in a file, database, etc. in the recording medium. For example, when a plurality of entries each having an attribute value of a first attribute associated with an attribute value of a second attribute are stored in the recording medium, the CPU 1212 may search for an entry whose attribute value of the first attribute matches a specified condition from among the plurality of entries, read the attribute value of the second attribute stored in the entry, and thereby obtain the attribute value of the second attribute associated with the first attribute that satisfies a predetermined condition.

[0119] The above-described programs or software modules may be stored in a computer-readable storage medium on the computer 1200 or in the vicinity of the computer 1200. In addition, a recording medium such as a hard disk or a RAM provided in a server system connected to a dedicated communication network or the Internet can be used as a computer-readable storage medium, thereby providing the programs to the computer 1200 via the network.

[0120] The blocks in the flowcharts and block diagrams in the present embodiment may represent stages of a process in which an operation is performed or "parts" of an apparatus responsible for performing the operation. Particular stages and "parts" may be implemented by dedicated circuitry, programmable circuitry provided with computer-readable instructions stored on a computer-readable storage medium, and / or a processor provided with computer-readable instructions stored on a computer-readable storage medium. The dedicated circuitry may include digital and / or analog hardware circuits, and may include integrated circuits (ICs) and / or discrete circuits. The programmable circuitry may include reconfigurable hardware circuits, such as, for example, field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), and the like, including AND, OR, XOR, NAND, NOR, and other logical operations, flip-flops, registers, and memory elements.

[0121] A computer-readable storage medium may include any tangible device capable of storing instructions that are executed by a suitable device, such that a computer-readable storage medium having instructions stored thereon comprises an article of manufacture that includes instructions that can be executed to create means for performing the operations specified in the flowcharts or block diagrams. Examples of computer-readable storage media may include electronic storage media, magnetic storage media, optical storage media, electromagnetic storage media, semiconductor storage media, and the like. More specific examples of computer-readable storage media may include floppy disks, diskettes, hard disks, random access memories (RAMs), read-only memories (ROMs), erasable programmable read-only memories (EPROMs or flash memories), electrically erasable programmable read-only memories (EEPROMs), static random access memories (SRAMs), compact disk read-only memories (CD-ROMs), digital versatile disks (DVDs), Blu-ray disks, memory sticks, integrated circuit cards, and the like.

[0122] The computer readable instructions may include either assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk®, JAVA®, C++, etc., and conventional procedural programming languages ​​such as the “C” programming language or similar programming languages.

[0123] Computer readable instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, or to a programmable circuit, either locally or over a local area network (LAN), a wide area network (WAN), such as the Internet, etc., to cause the processor of the general purpose computer, special purpose computer, or other programmable data processing apparatus, or to a programmable circuit, to execute the computer readable instructions to generate means for performing the operations specified in the flowcharts or block diagrams. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers, etc.

[0124] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0125] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before" or "prior to," and that the process may be performed in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, it does not mean that the process must be performed in this order. [Explanation of symbols]

[0126] 10 system, 20 network, 50 sign, 52 sign, 54 sign, 100 mobile object, 102 storage unit, 104 communication unit, 106 location information acquisition unit, 150 communication antenna, 200 base station, 202 base station, 204 base station, 220 coverage area, 222 coverage area, 224 coverage area, 250 communication antenna, 252 communication antenna, 254 communication antenna, 256 communication unit, 300 base station, 320 coverage area, 400 notification device, 420 coverage area, 1200 computer, 1210 host controller, 1212 CPU, 1214 RAM, 1216 graphic controller, 1218 display device, 1220 input / output controller, 1222 communication interface, 1224 storage device, 1226 DVD drive, 1227 DVD-ROM, 1230 ROM, 1240 I / O chip, 1242 keyboard

Claims

1. A moving body, A first base station; Equipped with the mobile unit and the first base station perform mobile communication such that a product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile unit and the first base station using radio waves with a frequency in the terahertz band is proportional to a square of a cosecant of an elevation / depression angle in a propagation direction of the radio waves; When the mobile unit establishes mobile communication with the first base station, the mobile unit transmits an establishment request to the first base station, the establishment request including communication antenna information indicating a communication antenna of the mobile unit; the first base station performs mobile communication with the mobile unit based on the communication antenna information included in the establishment request; When the mobile object has a communication antenna having an antenna gain proportional to the first power of the cosecant of the elevation / depression angle, the first base station performs mobile communication with the mobile object using the communication antenna having an antenna gain proportional to the first power of the cosecant of the elevation / depression angle; When the mobile object has a communication antenna whose antenna gain is non-directional with respect to the elevation / depression angle, the first base station performs mobile communication with the mobile object using a communication antenna whose antenna gain is proportional to the square of the cosecant of the elevation / depression angle. Communication systems.

2. The received power of the radio wave (P ＲＥ ) satisfies the following formula, [0010] Here, P ＴＲ is the transmission power of the radio wave, and G ＴＲ is the antenna gain of the communication antenna at the transmitting side, and G ＲＥ is the antenna gain of the communication antenna on the receiving side, λ is the wavelength of the radio wave, h is the altitude difference between the altitude of the communication antenna on the transmitting side and the altitude of the communication antenna on the receiving side, and θ is the elevation / depression angle. The communication system according to claim 1 .

3. the mobile unit performs mobile communication with a second base station having a coverage area including the coverage area of ​​the first base station, using radio waves with a frequency lower than the terahertz band, receives first presence information from the second base station indicating that the first base station is present within the coverage area of ​​the second base station, and performs mobile communication with the first base station based on the first presence information; 3. A communication system according to claim 1 or 2.

4. Notification device Further equipped with the notification device is placed outside a coverage area of ​​the first base station, and transmits, to the mobile object, second presence information indicating that the first base station is present within a predetermined range from the notification device, using radio waves with a terahertz band frequency; the mobile unit performs mobile communication with the first base station based on the second presence information.

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

5. A moving body, Base station and Equipped with the mobile unit and the base station perform mobile communication such that a product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile unit and the base station using radio waves with a frequency in the terahertz band is proportional to a square of a cosecant of an elevation / depression angle in a propagation direction of the radio waves; The received power (P RE ) of the radio wave satisfies the following formula: [0025] Here, P TR is the transmission power of the radio wave, G TR is the antenna gain of the communication antenna on the transmitting side, G RE is the antenna gain of the communication antenna on the receiving side, λ is the wavelength of the radio wave, h is the altitude difference between the altitude of the communication antenna on the transmitting side and the altitude of the communication antenna on the receiving side, and θ is the elevation / depression angle. Communication systems.

6. A moving body, A first base station; Equipped with the mobile unit and the first base station perform mobile communication such that a product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile unit and the first base station using radio waves with a frequency in the terahertz band is proportional to a square of a cosecant of an elevation / depression angle in a propagation direction of the radio waves; the mobile unit performs mobile communication with a second base station having a coverage area including the coverage area of ​​the first base station, using radio waves with a frequency lower than the terahertz band, receives presence information from the second base station indicating that the first base station is present within the coverage area of ​​the second base station, and performs mobile communication with the first base station based on the presence information; Communication systems.

7. A moving body, A base station; Notification device and Equipped with the mobile unit and the base station perform mobile communication such that a product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile unit and the base station using radio waves with a frequency in the terahertz band is proportional to a square of a cosecant of an elevation / depression angle in a propagation direction of the radio waves; the notification device is placed outside a coverage area of ​​the base station, and transmits to the mobile object, using radio waves with a terahertz frequency band, presence information indicating that the base station is present within a predetermined range from the notification device; The mobile unit performs mobile communication with the base station based on the presence information. Communication systems.

8. A mobile object, a communication antenna used for mobile communication between the mobile unit and a base station; a communication unit that performs mobile communication with the base station using a communication antenna provided in the mobile unit such that a product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile unit and the base station using radio waves with a frequency in the terahertz band is proportional to a square of a cosecant of an elevation / depression angle in a propagation direction of the radio waves; Equipped with The received power (P RE ) of the radio wave satisfies the following formula: [0030] Here, P TR is the transmission power of the radio wave, G TR is the antenna gain of the communication antenna on the transmitting side, G RE is the antenna gain of the communication antenna on the receiving side, λ is the wavelength of the radio wave, h is the altitude difference between the altitude of the communication antenna on the transmitting side and the altitude of the communication antenna on the receiving side, and θ is the elevation / depression angle. Mobile body.

9. The moving body according to claim 8 , wherein an antenna gain of the communication antenna included in the moving body is proportional to a first power of a cosecant of the elevation / depression angle.

10. A moving object, a first communication antenna used for mobile communication between the mobile object and a first base station using radio waves having a frequency in the terahertz band; a second communication antenna used for mobile communication between the mobile unit and a second base station having a coverage area including the coverage area of ​​the first base station, the second communication antenna using radio waves having a frequency lower than the terahertz band; a communication unit that performs mobile communication with the first base station using the first communication antenna such that a product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile unit and the first base station is proportional to a square of a cosecant of an elevation / depression angle in a propagation direction of the radio wave; Equipped with the communication unit performs mobile communication with the second base station using the second communication antenna, receives presence information from the second base station indicating that the first base station is present within the coverage area of ​​the second base station, and performs mobile communication with the first base station based on the presence information. Mobile body.

11. A moving object, a communication antenna used for mobile communication between the mobile object and a base station using radio waves of a terahertz band frequency, and for wireless communication between the mobile object and a notification device located outside a coverage area of ​​the base station using radio waves of a terahertz band frequency; a communication unit that performs mobile communication with the base station using the communication antenna provided in the mobile unit such that the product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile unit and the base station is proportional to the square of the cosecant of an elevation / depression angle in the propagation direction of the radio wave; Equipped with the communication unit performs wireless communication with the notification device using the communication antenna equipped in the mobile body, receives presence information from the notification device indicating that the base station is present within a predetermined range from the notification device, and performs mobile communication with the base station based on the presence information. Mobile body.

12. A program for causing a computer to function as the mobile body according to any one of claims 8, 10 and 11 when executed by the computer.

13. A base station, a first communication antenna for use in mobile communication between a mobile unit and the base station; a second communication antenna used for mobile communication between the mobile unit and the base station; a communication unit that performs mobile communication with the mobile body using the first communication antenna or the second communication antenna such that a product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile body and the base station using radio waves with a terahertz band frequency is proportional to a square of a cosecant of an elevation / depression angle in a propagation direction of the radio waves; Equipped with the communication unit receives, from the mobile object, a request for establishment including communication antenna information indicating a communication antenna of the mobile object, and performs mobile communication with the mobile object based on the communication antenna information included in the request for establishment; When the mobile body has a communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation / depression angle, the communication unit performs mobile communication with the mobile body using the first communication antenna whose antenna gain is proportional to the first power of the cosecant of the elevation / depression angle; When the mobile object has a communication antenna whose antenna gain is non-directional with respect to the elevation / depression angle, the communication unit performs mobile communication with the mobile object using the second communication antenna whose antenna gain is proportional to the square of the cosecant of the elevation / depression angle. Base station.

14. A base station, a communication antenna used for mobile communication between a mobile unit and the base station; a communication unit that performs mobile communication with the mobile body using a communication antenna provided in the base station such that the product of an antenna gain of a communication antenna on a transmitting side and an antenna gain of a communication antenna on a receiving side in mobile communication between the mobile body and the base station using radio waves with a frequency in the terahertz band is proportional to the square of the cosecant of an elevation / depression angle in the propagation direction of the radio waves; Equipped with The received power (P RE ) of the radio wave satisfies the following formula: [0045] Here, P TR is the transmission power of the radio wave, G TR is the antenna gain of the communication antenna on the transmitting side, G RE is the antenna gain of the communication antenna on the receiving side, λ is the wavelength of the radio wave, h is the altitude difference between the altitude of the communication antenna on the transmitting side and the altitude of the communication antenna on the receiving side, and θ is the elevation / depression angle. Base station.

15. A program for causing a computer to function as the base station according to claim 13 or 14 when executed by the computer.

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