JP2022064611A - Mobile radio communication system - Google Patents

Abstract

To provide stable mobile radio communication without omission by receiving with an antenna on a rear side in a travel direction.SOLUTION: Two or more antennas 20 are installed facing a travel direction on a mobile body 2 for the travelling mobile body 2 to wirelessly communicate with an outside ground radio station 3. A current travelling position is acquired. Based on the acquired current travelling position and the position of the ground radio station 3, an antenna 20 that transmits and receives transmission information to/from a terminal device 6 is selected.SELECTED DRAWING: Figure 2

Description

The present invention relates to a mobile radio communication system in which a moving mobile body wirelessly communicates with an external terrestrial radio station.

Conventionally, a mobile wireless communication system in which a mobile body such as a train or a vehicle performs wireless communication with an external terrestrial radio station has been proposed (see, for example, Non-Patent Document 1).

In this mobile radio communication system, for example, when the mobile body is a train, terrestrial radio stations are scattered in advance along the track on which the train travels. Then, the transmission information is distributed by wireless communication from the terrestrial radio station to the train traveling on the track, or the transmission information transmitted from the traveling train is transmitted by the terrestrial radio station by wireless communication. As a result, necessary information can be sent to the driver who drives the train and the conductor who controls the inside of the train via the transmission information from the terrestrial radio station, and information on various events and events that have occurred in the train can be sent. It becomes possible to transmit to a terrestrial radio station via this transmission information.

In particular, wireless communication between a terrestrial radio station and a train often uses the millimeter wave band. Since the millimeter wave band has strong straightness, it is suitable for railways with a long service area in a straight line, has a wide frequency range that can be used, and has the characteristics of being able to transmit a large amount of information in a short time. Therefore, by utilizing millimeter-wave band wireless communication, it is necessary to transmit a large amount of information in order to control trains and monitor the condition of vehicles, and to secure a large amount of communication resources for passengers and to provide abundant information. It will be possible to realize the provision.

Yukiya Tateishi, Tetsunori Hattori, Kunihiro Kawasaki, "Millimeter Wave Communication in Railways", Shingaku Giho, MWP2013-48, pp.7-12, Nov.2013

In the case of realizing the mobile wireless communication system described above, if there is only one antenna of the train, especially in a short-range wireless communication system such as a millimeter wave band, the train is on the ground by the time all the transmission information is received. It may be separated from the radio station. Therefore, in order to stably transmit and receive transmission information by wireless communication, antennas are provided at a plurality of locations different from each other in the traveling direction, and transmission information that cannot be received by the antenna on the front side in the traveling direction is traveled. It is necessary to receive the signal at the antenna on the rear side of the direction, but the current situation is that no technology that can realize this has been proposed in the past.

Therefore, the present invention has been devised in view of the above-mentioned problems, and an object thereof is a mobile wireless communication system in which a moving mobile body wirelessly communicates with an external terrestrial radio station. In consideration of the case where the train is separated from the terrestrial radio station by the time all the transmission information is received under the short-range wireless communication method such as the millimeter wave band, the locations are different from each other in the traveling direction. A mobile wireless communication system that can realize stable mobile wireless communication without omission by providing an antenna and receiving transmission information that cannot be received by the antenna on the front side in the traveling direction at the antenna on the rear side in the traveling direction. Is to provide.

In order to solve the above-mentioned problems, the present inventors have arranged two or more moving bodies on the moving body in the traveling direction in order to wirelessly communicate with an external terrestrial radio station. We have invented a mobile radio communication system in which the antennas are arranged and an antenna for transmitting and receiving transmission information to and from the terminal device is selected based on the current traveling position and the position of the terrestrial radio station.

The mobile radio communication system according to the first invention is a mobile radio communication system in which a moving mobile body wirelessly communicates with an external terrestrial radio station, and the mobile body communicates with the terrestrial radio station. Antennas arranged at two or more positions that are different from each other in the traveling direction for wireless communication of transmission information, terminal devices that transmit and receive the transmission information to and from the antennas, and traveling to acquire the current traveling position. A selection means for selecting an antenna for transmitting / receiving the transmission information to the terminal device based on the position acquisition means, the current travel position acquired by the travel position acquisition means, and the position of the terrestrial radio station. It is characterized by having.

In the mobile radio communication system according to the second invention, in the first invention, the selection means acquires the position of each antenna according to the current traveling position acquired by the traveling position acquisition means a plurality of times. , The calculated position S is obtained from the acquired positions (x ₁ , x ₂ , ..., X _n ) based on the following equation (1) or (2), and the calculated position S and the above-mentioned terrestrial radio are used. Select an antenna for transmitting and receiving the transmission information to the terminal device based on the position of the station. S = a ₁ × x ₁ + a ₂ × x ₂ + ... + an _n x _n (1)
S = a ₁ x x ₁ x a ₂ x x ₂ x ... x an _n x _n (2)
( _{A 1} to an are predetermined coefficients, _n is the number of acquisitions of the antenna position)
It is characterized by.

In the mobile wireless communication system according to the third invention, in the first invention or the second invention, the terminal device has the transmission information received through one of the antennas and the transmission information received through the other antennas. It is characterized in that and is combined into one transmission information.

In the mobile radio communication system according to the fourth invention, in the first invention or the second invention, the terrestrial radio station is arranged over two or more in the traveling direction, and the selection means is the traveling position acquisition means. Based on the position of each of the antennas according to the current traveling position acquired by the above and the position of each of the terrestrial radio stations, the antenna for transmitting and receiving the transmission information to the terminal device is attached to each of the terrestrial radio stations. It is characterized by selecting each time.

In the mobile radio communication system according to the fifth invention, in the fourth invention, the selection means is based on the transmission information received from the first terrestrial radio station located on one side of the traveling direction, and the other side of the traveling direction. It is characterized in that it determines whether or not to transmit the transmission information from the second terrestrial radio station located in the terminal device.

The mobile radio communication system according to the sixth invention is the mobile radio communication system according to the first to fifth inventions, wherein the mobile body is a train traveling on a line, and the terrestrial radio station is provided on the roadside of the line. It is characterized by performing wireless communication in the millimeter wave band with a mobile body.

According to the present invention having the above-described configuration, when the data transmitted from the terrestrial radio station has a large capacity such as in-vehicle advertisement information and various video contents, the data can be driven even by wireless communication in the millimeter wave band. It may not be possible to receive all the transmission information only with the antenna located on the front side in the direction. In particular, such a case may occur when the moving body has a particularly high moving speed such as the Shinkansen. In such a case, the remaining transmission information can be received from the terrestrial radio station by the antenna located on the rear side in the traveling direction. Such a processing operation can be realized by selecting an antenna by a selection unit based on the positional relationship of each antenna with respect to the position of the terrestrial radio station. As a result, stable mobile wireless communication can be realized without omission by receiving the transmission information that cannot be received by the antenna on the front side in the traveling direction at the antenna on the rear side in the traveling direction.

FIG. 1 is an overall schematic view of a mobile wireless communication system to which the present invention is applied. FIG. 2 is a diagram showing a block configuration inside a moving body. FIG. 3 is a diagram for explaining the operation of the mobile wireless communication system to which the present invention is applied. FIG. 4 is another diagram for explaining the operation of the mobile wireless communication system to which the present invention is applied. FIG. 5 is a diagram showing an example of a simulation in the case of transmitting terrestrial radio station data.

Hereinafter, the mobile wireless communication system to which the present invention is applied will be described in detail with reference to the drawings.

FIG. 1 is an overall schematic view of a mobile wireless communication system 1 to which the present invention is applied. The mobile radio communication system 1 is located between a mobile body 2 traveling in the traveling direction A, a plurality of terrestrial radio stations 3 scattered along the traveling direction of the moving object, and each terrestrial radio station 3. It is equipped with a central control station 4 capable of communicating by wire or wirelessly.

The moving body 2 will be described by taking a train traveling on the railroad track 5 as an example in the following description, but the present invention is not limited to this, and is not limited to this, but is not limited to monorails, vehicles such as passenger cars, buses, and trucks, motorcycles, aircraft, and the like. , Includes all moving objects. In the mobile body 2, one or more terminal devices 6 are set internally.

Assuming that the mobile body 2 is a train, the terrestrial radio station 3 is a fixed base station arranged on the shoulder of a track 5 on which the train travels. The terrestrial radio station 3 transmits transmission information to the traveling mobile body 2 by wireless communication. Further, the terrestrial radio station 3 receives transmission information from the traveling mobile body 2 by wireless communication. The terrestrial radio station 3 may use the millimeter wave band for wireless communication with the mobile body 2. By using the millimeter wave band for this wireless communication, a large amount of information can be transmitted in a short time, and it is necessary to transmit a lot of information for controlling trains and monitoring the condition of vehicles, and mobile objects. It is possible to secure a large amount of communication resources and provide abundant information by the terminal device 6 installed in 2. The terrestrial radio station 3 may form a small-scale service area called a microcell, and may transmit content specific to the service area to the mobile body 2 as transmission information from each of them.

The central control station 4 is a server that receives information transmitted from the terrestrial radio station 3 and stores it. In the terrestrial radio station 3, information from a large number of mobile bodies 2 is transmitted, and the information is transmitted to the central control station 4. Therefore, the central control station 4 can concentrate the information acquired in each mobile body 2 in one pole. By centralizing such information, the central control station 4 can compile the information acquired by the mobile body 2 showing the more detailed situation in each region and each time zone into one database. , Can be used for various purposes.

Further, the central control station 4 transmits contents and information to be distributed to the mobile body 2 to the terrestrial radio station 3. As a result, the terrestrial radio station 3 can convert the information transmitted from the central control station 4 into transmission information and distribute it to the mobile body 2 via wireless communication. In particular, disaster information and highly real-time information in each region should be collectively acquired or generated by the central control station 4, and the information should be arranged for each base of the terrestrial radio station 3 as necessary for distribution. Convenience can be increased.

Next, the detailed configuration of the moving body 2 will be described. FIG. 2 shows a block configuration inside the moving body 2.

The moving body 2 is a selection unit that selects a plurality of antennas 20a and 20b, a terminal device 6 capable of transmitting and receiving information to and from the antennas 20, and antennas 20a and 20b for transmitting and receiving transmission information to and from the terminal device 6. 24, a traveling position acquisition unit 23 connected to the selection unit 24, and an operation control unit 21 for controlling the operation of the moving body 2 itself are provided.

The terminal device 6 is an electronic device preliminarily arranged at different positions in the moving body 2 in the traveling direction A, and informs passengers and occupants of, for example, smartphones, tablet terminals, PCs, display terminals, and the like. It is composed of a device equipped with a user interface for displaying or inputting a command, but is not limited to this. The terminal device 6 may be composed of various electronic devices, devices, sensors, etc. that are not provided with any user interface. Further, the terminal device 6 is not limited to the one previously arranged inside the mobile body 2, and may be composed of a mobile type terminal carried by passengers and occupants. Examples of this mobile terminal include smartphones, tablet terminals, notebook PCs, wearable terminals and the like.

The operation control unit 21 includes all configurations for controlling the operation of the moving body 2, includes a handle, an accelerator, a brake, a gear, and the like, and the driving operation by the driver is reflected in the movement of the moving body 2. Of course, the operation control unit 21 may be equipped with autopilot and automatic driving functions.

The traveling position acquisition unit 23 acquires the current traveling position of the moving body 2 moved by the operation by the operation control unit 21. The traveling position to be acquired may be set on the system side each time as to which position of the moving body 2 that is continuously connected in the traveling direction A for a long time, or the head, the tail, and the second car from the head of the moving body 2. It is necessary to set at least one place such as the head of the vehicle. The traveling position acquisition unit 23 may acquire the traveling position of the moving body 2 by using, for example, GPS (Global Positioning System), may acquire it through a beacon, or may acquire the traveling position through a beacon, or may be acquired on the ground as a carrier base station. It may be acquired by positioning by radio waves from the radio station 3. The traveling position acquisition unit 23 may continuously acquire the current traveling position. The time interval for acquiring the traveling position may be any time interval such as seconds, milliseconds, microseconds, nanoseconds, picoseconds, and the like. The traveling position acquisition unit 23 transmits to the selection unit 24 each time the traveling position at the present time in the moving body 2 acquired in this way is acquired.

The antennas 20 are arranged at two or more positions different from each other in the traveling direction. In the example of FIG. 2, an example is shown in which an antenna 20a arranged on the front side in the traveling direction and an antenna 20b arranged on the rear side in the traveling direction are provided. A radio signal including transmission information in the millimeter wave band is received from the terrestrial radio station 3 and converted into an electric signal. The antenna 20 distributes the transmission information converted into this electric signal to each terminal device 6. Further, the antenna 20 converts the transmission information consisting of the electric signal transmitted from the terminal device 6 into a radio signal, and transmits this to the terrestrial radio station 3.

Incidentally, it is premised that the position information regarding the position of each antenna 20 in the traveling direction A is known, and all of these are stored in the selection unit 24.

The selection unit 24 selects the antenna 20 to be transmitted / received between the terrestrial radio station 3 and the terminal device 6 among the antennas 20a and 20b. As a method of selecting the antenna 20 for transmitting the transmission information, the connection circuit connecting the terminal device 6 and the antennas 20a and 20b may be switched on or off, or the transmission information to be transmitted may be selected once. The unit 24 may control whether to receive the signal and distribute it to the terminal device 6 selected by the selection unit 24 again, or not to distribute it to the terminal device 6.

When transmitting the transmission information generated by the terminal device 6 to the terrestrial radio station 3 via the antenna 20, the selection unit 24 also selects the antenna 20 that wirelessly communicates with the terrestrial radio station 3. As a method of selecting the antenna 20 that carries out the wireless communication of the transmission information, the connection circuit connecting the terminal device 6 and the antenna 20 may be switched on or off, or the signal is transmitted from the terminal device 6. The transmission information may be received once by the selection unit 24 and transmitted only to the antennas 20a and 20b selected by the selection unit 24. When the transmission information is transmitted from the terminal device 6 by short-range wireless communication, the selection unit 24 may select the antennas 20a and 20b for transmitting the transmission information by controlling the transmission information.

Further, the selection unit 24 stores the position of each terrestrial radio station 3 in the traveling direction A. The selection unit 24 receives the current travel position of the moving body 2 acquired by the travel position acquisition unit 23. The selection unit 24 has known position information regarding the positions of the antennas 20a and 20b in the traveling direction A, and stores all of them. The terminal device 6 is based on the current traveling position of the moving body 2 acquired by the traveling position acquisition unit 23, the positions of the antennas 20a and 20b in the traveling direction A, and the positions of the terrestrial radio station 3. Select the antenna 20 for transmitting and receiving transmission information between the antennas 20. Hereinafter, the detailed operation by the selection unit 24 will be described.

3 (a) to 3 (b) show the terminal device 6, the antennas 20a and 20b, and the terrestrial radio station 3 in the mobile body 2 in order to explain the operation of the mobile wireless communication system 1 to which the present invention is applied. Only the positional relationship with and is extracted and described.

It is assumed that the mobile body 2 has approached a certain terrestrial radio station 3 in the process of traveling in the traveling direction A. When transmitting the transmission information from the terrestrial radio station 3 to the terminal device 6 via the antennas 20a and 20b, the selection unit 24 grasps the current traveling position of the mobile body 2 acquired by the traveling position acquisition unit 23. If the actual traveling position of the moving body 2 on the map can be acquired, the position information in the moving body 2 of the antennas 20a and 20b has already been acquired and is known, so that the traveling direction of the antennas 20a and 20b is known. The actual position on the map in A can be obtained.

Further, it is premised that the selection unit 24 stores the actual position on the map in the traveling direction A of each terrestrial radio station 3. Therefore, the selection unit 24 can grasp the positional relationship between the actual position on the map in the traveling direction A of the antennas 20a and 20b and the actual position on the map in the traveling direction A of the ground radio station 3. .. Then, the positional relationship between the antennas 20a and 20b and the traveling direction A of the terrestrial radio station 3 can be grasped each time the position of the moving body 2 is detected by the traveling position acquisition unit 23. By continuously acquiring the current position detection of the moving body 2 by the traveling position acquisition unit 23 in chronological order, the positional relationship between the antennas 20a and 20b and the traveling direction A of the terrestrial radio station 3 is chronologically acquired. It becomes possible to grasp continuously.

When the antenna 20a is closest to the terrestrial radio station 3, the selection unit 24 selects only the antenna 20a, as shown in FIG. 3A, for example, as shown in FIG. 3A. Antenna 20b is not selected. When the antenna 20b is closest to the terrestrial radio station 3, the selection unit 24 selects only the antenna 20b, as shown in FIG. 3 (b), for example, as shown in FIG. 3 (b). Antenna 20a is not selected as a delivery destination.

That is, in the process of the moving body 2 moving in the traveling direction A, the antenna 20 close to the terrestrial radio station 3 also changes from the antenna 20a to the antenna 20b. Then, in the process of changing the antenna 20 close to the terrestrial radio station 3 from the antenna 20a to the antenna 20b, the selection of the antenna 20 to be the reception destination of the transmission information transmitted from the terrestrial radio station 3 is replaced. That is, by controlling the terrestrial radio station 3 to receive the transmission information via the antenna 20 adjacent to the terrestrial radio station 3 and not to receive the transmission information via the antenna 20 not close to the terrestrial radio station 3, the present invention has an excellent effect described below. Play.

For example, when the data sent from the terrestrial radio station 3 has a large capacity such as in-vehicle advertisement information and various video contents, the antenna located on the front side of the traveling direction A even for wireless communication in the millimeter wave band. It may not be possible to receive all the transmission information only with 20a. In particular, when the moving body 2 has a particularly high moving speed such as the Shinkansen, such a case may occur. In such a case, the remaining transmission information is received from the terrestrial radio station 3 by the antenna 20b located on the rear side of the traveling direction A. Such a processing operation can be realized by selecting the antenna 20 by the selection unit 24 based on the positional relationship of the antennas 20a and 20b with respect to the position of the terrestrial radio station 3.

That is, according to the present invention, the transmission information received by the antenna 20a located on the front side of the traveling direction A and the transmission information received by the antenna 20b located on the rear side of the traveling direction A are mutually transmitted on the terminal device 6 side. It may be combined into one transmission information.

The transmission information actually received by the antennas 20a and 20b is sent to the terminal device 6, respectively, but even if the terminal device 6 side performs a process of combining the transmission information sent from the antennas 20a and 20b with each other. Of course, it is also possible to manage and utilize the data separately from each other.

In the above description, the case where the antenna 20 is composed of two antennas 20a and 20b has been described as an example, but the present invention is not limited to this, and the same applies to the case where the antenna 20 has three or more antennas. In the process of changing the antenna 20 in the vicinity of the station 3, the selection of the antenna 20 to be the reception destination of the transmission information transmitted from the terrestrial radio station 3 is exchanged.

According to the present invention, any antenna 20 should be selected as long as it is based on the position of each antenna 20 that can be grasped through the current traveling position of the mobile body 2 and the position of the terrestrial radio station 3. However, the present invention is not limited to the above-described embodiment.

In addition to this, according to the present invention, the detection of the traveling position of the moving body 2 is continuously acquired, and the antenna 20 is selected and switched based on the plurality of continuously acquired traveling positions. You may.

In such a case, if a plurality of traveling positions are acquired over a certain period of time, the position information in the moving body 2 in each of the antennas 20a and 20b corresponding to each traveling position can be acquired in the same manner. If two traveling positions are acquired within a predetermined period, the position information P1 and P2 in each of the antennas 20a and 20b corresponding to each traveling position can be acquired. The acquired position information P1 and P2 of each of the antennas 20a and 20b are calculated based on the calculation formula. This is performed not only for one antenna 20a but also for the other antenna 20b. Then, the antenna 20 that transmits / receives transmission information to / from the terrestrial radio station 6 may be selected based on the calculation result of the position information of each antenna 20 and the positional relationship with the terrestrial radio station 3. As this calculation formula, any conventional calculation formula may be used, but it may be simplified and the position obtained by averaging the position information P1 and P2 of each antenna 20 may be output as the calculation result. In addition to averaging the position information, the calculation expression may be composed of, for example, an expression that adopts only the position information acquired first or the position information acquired later, or any of the position information P1 and P2. It may be configured by an arithmetic expression in which a desired weighting is set. Further, when the traveling position is acquired 3 or more within a predetermined period, the position information of each antenna 20 can be acquired 3 or more in the same manner. In such a case, the position information of 3 or more may be introduced into the calculation formula, and the position of each antenna 20 may be grasped based on the calculation result.

The position of each antenna 20 according to the acquired current traveling position is acquired multiple times, and the equation (1) or the acquired position of each antenna 20 (x ₁ , x ₂ , ..., X _n ) is used. Even if the calculated position S is obtained based on (2) and the antenna 20 for transmitting / receiving transmission information to the terminal device 6 is selected based on the calculated calculated position S and the position of the terrestrial radio station 3. good.
S = a ₁ x x ₁ + a ₂ x x ₂ + ... + an _n x _n (1)
( _{A 1} to an are predetermined coefficients, _n is the number of acquisitions of the antenna position)

Then, based on the obtained calculated position S and the position of the terrestrial radio station 3, the antenna 20 for transmitting / receiving transmission information to the terminal device 6 is selected.

For example, when the position is acquired twice per unit time for each antenna 20 for a unit time, the above equation (1) is expressed by S = a ₁ × x ₁ + a ₂ × x ₂ . If the average of the positions x ₁ and x ₂ of each antenna 20 is to be calculated, both a ₁ and a ₂ are 1/2, in other words, 1 / n. Further, if either one of the positions x ₁ and x ₂ of each antenna 20 is adopted, either one of a ₁ or a ₂ becomes 0. Further, if desired weighting is applied to the positions x ₁ and x ₂ of the antenna 20, the weighting can be set in advance for a ₁ and a ₂ , respectively.

_Here , a ₁ to an can be determined in advance on the system side or the user side, so that the calculated position S of the antenna 20 can be obtained for each vehicle under unified operation.

In the present invention, the calculation of the calculation position S is not limited to the above-described embodiment, and may be based on the following equation (2).

S = a ₁ x x ₁ x a ₂ x x ₂ x ... x an _n x _n (2)
Similarly, the calculated position S can be obtained by using the above (2).

4 (a) and 4 (b) show an example of receiving transmission information from a plurality of terrestrial radio stations 3. In the example of FIG. 4, an example in which transmission information different from each other is transmitted from the first terrestrial radio station 3a located on the front side in the traveling direction A and the second terrestrial radio station 3b located on the rear side in the traveling direction A. Shows. When the antenna 20a is the closest to the terrestrial radio station 3a, the selection unit 24 selects only the antenna 20a, as shown in FIG. 4A, for example, as shown in FIG. 4A. Antenna 20b is not selected. As a result, the transmission information from the terrestrial radio station 3a is transmitted to the terminal device 6 via the antenna 20a. When the antenna 20b is the closest to the terrestrial radio station 3b, the selection unit 24 selects only the antenna 20b, as shown in FIG. 4 (b), for example, as shown in FIG. 4 (b). Antenna 20a is not selected. As a result, the transmission information from the terrestrial radio station 3b is transmitted to the terminal device 6 via the antenna 20b.

In the above example, in the process in which the moving body 2 moves in the traveling direction A and the antenna 20 close to the terrestrial radio station 3 also changes from the antenna 20a to the antenna 20b, the transmission information is transmitted from the terrestrial radio station 3a on the front side. Transmission information is received via the antenna 20b via the 20a and from the terrestrial radio station 3b on the rear side, but the present invention is not limited to this, and the transmission information from the terrestrial radio stations 3a and 3b is received. The allocation of the receiving antennas 20a and 20b may be configured in any combination.

In the above description, the case where the antenna 20 is composed of two antennas 20a and 20b and the antenna 20 is composed of two terrestrial radio stations 3a and 3b has been described as an example, but the present invention is not limited thereto. The same applies to the case where the antenna 20 or the terrestrial radio station 3 is three or more, and the antenna 20 is the reception destination of the transmission information transmitted from the terrestrial radio station 3 in the process of changing the antenna 20 close to the terrestrial radio station 3. The selection of the antenna 20 is exchanged, and the antenna 20 for receiving the transmission information from the terrestrial radio station 3 is assigned.

The transmission information transmitted from the terrestrial radio stations 3a and 3b may be different from each other. For example, consider a case where a desired content is superimposed on this transmission information and transmitted from a terrestrial radio station 3 to a passenger via a terminal device 6. At this time, the transmission information transmitted from the terrestrial radio station 3a includes basic information for explaining the basic outline of the content, and the actual data of the content is included as the transmission information transmitted from the terrestrial radio station 3b. It shall be included.

In such a case, first, the transmission information is received from the terrestrial radio station 3a via the antenna 20a, and the basic information included in the transmission information is viewed to determine whether or not the content should be distributed to the terminal device 6. do. This determination may be made by the selection unit 24 or by the terminal device 6. As a result, when it is determined that the actual data of the content should be distributed, the selection unit is to receive the transmission information including the actual data from the terrestrial radio station 3b via the antenna 20b and transmit this to the terminal device 6. 24 controls. On the other hand, when it is determined that the actual data of the content should not be distributed, even when the transmission information including the actual data is received from the terrestrial radio station 3b via the antenna 20b, this is transmitted to the terminal device 6. The selection unit 24 controls to discard the data without transmitting it. At this time, the mobile body 2 may be set not to receive the transmission information via the antenna 20b instead of discarding the data.

As described above, according to the present invention, the terminal transmits the transmission information from the terrestrial radio station 3b located on the rear side of the traveling direction A based on the transmission information received from the terrestrial radio station 3a located on the front side of the traveling direction A. It may be decided whether or not to transmit to the device 6. As a result, it is possible to prevent the reception efficiency from being lowered by preventing the reception of unnecessary transmission information.

In such a case, conversely, based on the transmission information received from the terrestrial radio station 3b located on the rear side of the traveling direction A, the transmission information from the terrestrial radio station 3a located on the front side of the traveling direction A is transmitted to the terminal device 6. You may decide whether or not to send to. That is, whether or not to transmit the transmission information from the terrestrial radio station 3 located on the other side of the traveling direction A to the terminal device 6 based on the transmission information received from the terrestrial radio station 3 located on one side of the traveling direction A. May be decided.

In addition to this, according to the present invention, the relative positional relationship between the position of the antenna 20 and the position of the terrestrial radio station 3 may be acquired in advance. The relative positional relationship referred to here is not limited to the case where the position of the antenna 20 and the position of the terrestrial radio station 3 are substantially the same in the A direction, and may be diagonal to each other. For example, as shown in FIG. 3A, the relative positional relationship between the antenna 20b and the terrestrial radio station 3 is in an oblique direction. Such a relative positional relationship in the diagonal direction may be used, or may be substantially the same in the A direction as in the relative positional relationship between the antenna 20a and the terrestrial radio station 3 shown in FIG. 3 (a). May be good. The relative positional relationship may be defined by the relationship between the position coordinates of the position of the antenna 20 and the position of the terrestrial radio station 3, the angle of the line segment connecting these position coordinates, and the like.

When such a relative positional relationship is acquired in advance and the antenna 20 is actually selected, the acquired relative positional relationship is referred to. Then, when the position of the one antenna 20 according to the newly acquired current traveling position almost satisfies the relative positional relationship to be referred to with the position of the terrestrial radio station 3, the one terminal device is selected. You may do so.

In the above-mentioned example, the case where the antenna 20 for receiving the transmission information from the terrestrial radio station 3 is selected has been described as an example, but the description is not limited to this. On the contrary, when transmitting the transmission information to the terrestrial radio station 3 via the antenna 20, the same applies to the case where the antenna 20 to be transmitted is selected. For example, when it is desired to convert each sensing information acquired by the terminal device 6 and the fact that the content has not been successfully received on the terminal device 6 side into transmission information and transmit it to the terrestrial radio station 3, the current mobile body 2 is as described above. Of course, the optimum antenna 20 may be selected based on the position of each antenna 20 that can be grasped through the traveling position and the position of the terrestrial radio station 3.

In FIG. 5, as shown in FIG. 4, the antenna 20 is composed of antennas 20a and 20b, is composed of terrestrial radio stations 3a and 3b, and transmits basic information from the terrestrial radio station 3a and actual data of contents from the terrestrial radio station 3b. An example of simulation in the case is shown. The total data size sent from the terrestrial radio station 3 consists of the data size of the information from the terrestrial radio station 3a and the data size of the late information from the terrestrial radio station 3b. Here, as a result of confirming the content of the information, it is simulated how much the reception efficiency can be improved by not receiving the late information from the terrestrial radio station 3b. When the ratio of the data size of the above information to the data size of the late information is 0.1 and 0.5, it is shown that the reception efficiency with respect to the ratio of "unnecessary" information on the horizontal axis is improved, respectively. There is. In particular, when the ratio of the data size of the signal is 0.1, it can be seen that the reception efficiency can be doubled when the ratio of "unnecessary" information is 40%.

1 Mobile wireless communication system 2 Mobile 3 Ground radio station 4 Central control station 6 Terminal device 20 Antenna 21 Operation control unit 23 Travel position acquisition unit 24 Selection unit

Claims (6)

In a mobile radio communication system in which a moving mobile body wirelessly communicates with an external terrestrial radio station.
The above mobile is
Antennas arranged at two or more positions different from each other in the traveling direction for wirelessly communicating transmission information with the above-mentioned terrestrial radio station, and
A terminal device that sends and receives the transmission information to and from the antenna, and
A traveling position acquisition means for acquiring the current traveling position, and
It is characterized by including a selection means for selecting an antenna for transmitting and receiving the transmission information to the terminal device based on the current traveling position acquired by the traveling position acquisition means and the position of the terrestrial radio station. Mobile wireless communication system. The selection means acquires the position of each of the antennas according to the current traveling position acquired by the traveling position acquisition means a plurality of times, and the acquired positions of the antennas (x ₁ , x ₂ , ... , _Xn ), the calculated position S is obtained based on the following formula (1) or (2), and the transmission information is transmitted to the terminal device based on the calculated position S and the position of the terrestrial radio station. Select an antenna to send and receive S = a ₁ x x ₁ + a ₂ x x ₂ + ... + an _n x _n (1)
S = a ₁ x x ₁ x a ₂ x x ₂ x ... x an _n x _n (2)
( _{A 1} to an are predetermined coefficients, _n is the number of acquisitions of the antenna position)
The mobile wireless communication system according to claim 1. Claim 1 or 2 is characterized in that the terminal device combines the transmission information received via one of the antennas with the transmission information received via the other antenna to form one transmission information. The mobile wireless communication system described. The above-mentioned terrestrial radio stations are arranged over two or more in the traveling direction.
The selection means transmits the transmission information to the terminal device based on the positions of the antennas according to the current traveling position acquired by the traveling position acquisition means and the positions of the terrestrial radio stations. The mobile radio communication system according to claim 1 or 2, wherein the transmitting and receiving antennas are selected for each of the above-mentioned terrestrial radio stations. The selection means transfers the transmission information from the second terrestrial radio station located on the other side of the traveling direction to the terminal device based on the transmission information received from the first terrestrial radio station located on one side of the traveling direction. The mobile radio communication system according to claim 4, wherein it is determined whether or not to transmit. The above-mentioned moving body is a train running on a railroad track.
The mobile radio according to any one of claims 1 to 5, wherein the terrestrial radio station is provided on the roadside of the line and performs radio communication in a millimeter wave band with the mobile. Communications system.

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