JP2018067814A - Mobile communication device, mobile communication system, and communication method of mobile communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile communication device, a mobile communication system and a communication method of mobile communication device in which communication efficiency was improved by selecting an appropriate modulation system efficiently.SOLUTION: A mobile communication device 100 includes a modulation system selection history acquisition unit 2, and a modulation system selection unit 4, and a positional information acquisition unit 3. The modulation system selection history acquisition unit 2 acquires modulation system selection history related to at least one preceding mobile 201, i.e., the history indicating which modulation system was used by a mobile communication device mounted on the preceding mobile 201 for communication with a ground device 400 at which position on the route. With reference to the modulation system selection history related to at least one preceding mobile 201, acquired by the modulation system selection history acquisition unit 2, the modulation system selection unit 4 selects the modulation system used by the preceding mobile 201 at the position corresponding to the current position of the mobile 101.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mobile communication device, a mobile communication system, and a communication method for the mobile communication device.

  A mobile communication device mounted on a mobile body and communicating with a ground device selects an appropriate modulation method from a plurality of modulation methods and communicates with the ground device. For example, a mobile communication device that identifies a signal type, audio data, and non-audio data included in communication information and selects a modulation method is known (see, for example, Patent Document 1).

  Also, there is known a mobile communication device that selects another modulation scheme and transmits data again when a transmission error occurs in a certain modulation scheme a predetermined number of times (for example, see Patent Document 2).

JP-A-7-250117 JP 2005-515704 A

  In the conventional mobile communication device, when a transmission error occurs in a certain modulation method, another modulation method is selected and data is transmitted again, so that the communication efficiency is lowered.

  The present invention has been made to solve the above-described problems, and a mobile communication device, a mobile communication system, and a mobile communication that improve communication efficiency by efficiently selecting an appropriate modulation method. An object is to provide a communication method of an apparatus.

  A mobile communication device according to the present invention is a mobile communication device that is mounted on a mobile body and communicates with a ground device. The mobile communication device communicates with a modulation method selection history acquisition unit and a ground device. A modulation method selection unit that selects a modulation method to be used, and a position information acquisition unit that acquires a path along which the mobile body moves, a current position of the mobile body, and a direction in which the mobile body moves, Acquiring a modulation scheme selection history for at least one preceding moving body that moves ahead of the moving body in the same direction as the moving body on the same path as the moving body, and selects the modulation scheme for the preceding moving body The history is a history indicating which modulation method is used for communication with the ground device at which position on the route by the mobile communication device mounted on the preceding mobile body. The acquisition department Obtained was, with reference to modulation scheme selection history for at least one previous moving object, selects a modulation scheme used in the prior mobile at a position corresponding to the current position of the moving body.

  A communication method of a mobile communication device according to the present invention is a communication method of a mobile communication device that is mounted on a mobile body and communicates with a ground device, wherein (a) a path along which the mobile body moves, A step of acquiring a current position and a direction in which the moving body moves; and (b) at least one preceding movement that precedes the moving body in the same direction as the moving body in the same path as the moving path of the moving body. Obtaining a modulation method selection history relating to a mobile object, and a modulation method selection history relating to a preceding mobile object is determined based on which modulation method the mobile communication device mounted on the preceding mobile object is at which position on the route. (C) modulation used by the preceding mobile body at a position corresponding to the current position of the mobile body with reference to the modulation method selection history for at least one previous mobile body Direction Further comprising the step of selecting a.

  According to the mobile communication device and the communication method of the mobile communication device according to the present invention, the mobile communication device acquires a modulation method selection history related to a preceding mobile, and refers to the history to communicate with a ground device. Select the modulation method to be used. This increases the possibility of selecting an appropriate modulation scheme with few transmission errors. Accordingly, it is possible to efficiently communicate by reducing the time required to search for an appropriate modulation method and the time required to retransmit data in which an error has occurred by changing the modulation method.

1 is a diagram showing a configuration of a mobile communication device according to Embodiment 1. FIG. 1 is a diagram showing a configuration of a mobile communication system according to Embodiment 1. FIG. 2 is a diagram showing a hardware configuration of a mobile communication device according to Embodiment 1. FIG. 3 is a flowchart showing an operation of the mobile communication device according to the first embodiment. FIG. 3 is a diagram showing a configuration of a mobile communication system according to a second embodiment. FIG. 6 is a diagram showing a configuration of a mobile communication system according to a third embodiment. It is a figure which shows the structure of the mobile communication apparatus which concerns on Embodiment 4. FIG. FIG. 10 is a diagram showing an operation of the mobile communication device according to the fourth embodiment. FIG. 10 is a diagram showing a configuration of a mobile communication apparatus according to a fifth embodiment. FIG. 10 is a diagram showing a configuration of a mobile communication system according to a fifth embodiment. 10 is a flowchart showing an operation of the mobile communication device according to the fifth embodiment.

<Embodiment 1>
<Configuration>
FIG. 1 is a diagram showing a configuration of mobile communication apparatus 100 according to the first embodiment. FIG. 2 is a diagram showing a configuration of the mobile communication system in the first embodiment. The mobile communication device 100 is mounted on the mobile body 101 and communicates with the ground device 400. The moving body 101 is a train that moves on a track, for example. Further, it is assumed that the position of the ground device 400 is fixed.

  As shown in FIG. 1, the mobile communication device 100 includes a transmission / reception unit 1, a modulation method selection history acquisition unit 2, a position information acquisition unit 3, and a modulation method selection unit 4. The modulation method selection unit 4 selects a modulation method used for communication with the ground device 400 from a plurality of modulation methods. The modulation scheme is selected for each of the uplink and downlink. Here, the uplink is a line for transmitting data from the mobile communication device 100 to the ground device 400. The downlink is a line for transmitting data from the ground device 400 to the mobile communication device 100.

  Here, the plurality of modulation schemes are, for example, a plurality of modulation schemes having different numbers of signal points, such as a two-phase shift keying modulation method (BPSK), a four-phase shift keying modulation method (QPSK), and an eight-phase shift keying modulation method. (8PSK), 16 phase shift keying (16PSK), and the like. Further, the plurality of modulation schemes may include a plurality of frequency shift keying schemes (FSK) having different numbers of signal points. Further, the plurality of modulation schemes may include a plurality of amplitude shift keying schemes (ASK) having different numbers of signal points. The plurality of modulation schemes may include a plurality of quadrature amplitude modulation schemes (QAM) having different numbers of signal points.

  The position information acquisition unit 3 acquires a route along which the moving body 101 moves, a current position of the moving body 101, and a direction in which the moving body 101 moves. Here, the path along which the moving body 101 moves means, for example, a route along which the moving body 101 is moving. Further, the current position of the moving body 101 is the current position on the path of the moving body 101. The current position on the route of the moving body 101 is expressed by, for example, about a kilometer from the reference position. Further, the current position may be acquired by a GPS signal, for example. Further, the direction in which the moving body 101 moves means whether the moving body 101 is moving in the upward direction or the downward direction when the route is a train route.

  The modulation scheme selection history acquisition unit 2 acquires a modulation scheme selection history. The modulation method selection history acquired by the modulation method selection history acquisition unit relates to the preceding moving body 201 that moves ahead of the moving body 101 in the same direction as the moving body 101 along the same path as the moving body 101 moves. It is a history.

  The modulation method selection history related to the preceding mobile body 201 is a history indicating which modulation method is used for communication with the ground device 400 at which position on the path of the mobile communication device mounted on the preceding mobile body 201. . The modulation scheme selection history for the preceding moving body 201 is represented by a modulation scheme selection history R201 in FIG.

  The modulation method selection unit 4 refers to the modulation method selection history R201 regarding the preceding moving body 201 acquired by the modulation method selection history acquisition unit 2, and is used by the preceding moving body 201 at a position corresponding to the current position of the moving body 101. Select the modulation method. The transmission / reception unit 1 communicates with the ground device 400 using the modulation method selected by the modulation method selection unit 4.

  FIG. 3 is a diagram illustrating a hardware configuration of the mobile communication device 100. The functions of the transmission / reception unit 1 and the modulation scheme selection history acquisition unit 2 are realized by the transmission antenna HW1, the transmission circuit HW2, the reception antenna HW3, and the reception circuit HW4.

  The function of the position information acquisition unit 3 is realized by, for example, the GPS signal receiving circuit HW5 and the processing circuit HW6. The function of the modulation scheme selection unit 4 is realized by the processing circuit HW6. Even if the processing circuit HW6 is dedicated hardware, a CPU (Central Processing Unit, a central processing unit, a processing unit, a processing unit, a microprocessor, a microcomputer, a microcontroller, and a processor that executes a program stored in the memory HW7 , Or DSP).

  When the processing circuit HW6 is dedicated hardware, the processing circuit HW6 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof. .

  When the processing circuit HW6 is a CPU, the functions of the position information acquisition unit 3 and the modulation method selection unit 4 are realized by software, firmware, or a combination of software and firmware. Software and firmware are described as programs and stored in the memory HW7. The processing circuit HW6 implements the functions of the position information acquisition unit 3 and the modulation method selection unit 4 by reading and executing the program stored in the memory HW7. It can also be said that this program causes a computer to execute the procedures and methods of the position information acquisition unit 3 and the modulation method selection unit 4. Here, the memory HW7 is, for example, a nonvolatile or volatile semiconductor memory such as RAM, SDRAM, ROM, flash memory, EPROM, EEPROM, magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD All storage media such as are applicable.

  The functions of the position information acquisition unit 3 and the modulation scheme selection unit 4 may be partially realized by dedicated hardware and partially realized by software or firmware.

<Operation>
FIG. 4 is a flowchart showing the operation of the mobile communication device 100. As shown in FIG. 2, the preceding moving body 201 moves ahead of the moving body 101 in the same direction as the moving direction of the moving body 101 on the same route as the moving body 101 on which the mobile communication device 100 is mounted. Assuming that

  First, the position information acquisition unit 3 acquires a route along which the moving body 101 moves, a current position of the moving body 101, and a direction in which the moving body 101 moves (step S101).

  Next, the modulation scheme selection history acquisition unit 2 acquires a modulation scheme selection history related to the preceding moving body 201 (that is, the modulation scheme selection history R201 in FIG. 2) (step S102). Here, the modulation method selection history regarding the preceding mobile body 201 is transmitted from the preceding mobile body 201 to the ground device 400 and stored in the storage unit of the ground device 400. The modulation scheme selection history acquisition unit 2 acquires a modulation scheme selection history R201 related to the preceding moving body 201 through communication with the ground device 400.

  Next, the modulation scheme selection unit 4 refers to the modulation scheme selection history related to the preceding moving body 201 and selects the modulation scheme used by the preceding moving body 201 at a position corresponding to the current position of the moving body 101 (step S103). Referring to the modulation scheme selection history R201 in FIG. 2, the modulation scheme used by the preceding mobile unit 201 at the position corresponding to the current position of the mobile unit 101 is scheme D on the uplink and scheme B on the downlink. . Therefore, the modulation scheme selection unit 4 of the mobile communication device 100 selects the modulation scheme D on the uplink and selects the modulation scheme B on the downlink.

  Then, the transmission / reception unit 1 of the mobile communication device 100 communicates with the ground device 400 using the modulation method selected by the modulation method selection unit 4 (step S104).

  When the transmission capacity of the modulation scheme selected by the modulation scheme selection unit 4 is less than or equal to a predetermined value, the modulation scheme selection unit 4 may reselect a modulation scheme having a transmission capacity larger than the predetermined value. Here, the predetermined value of the transmission capacity is, for example, the number of signal points in the modulation scheme. For example, when a modulation scheme with 4 or less signal points (for example, 2PSK, 4PSK, etc.) is selected, the modulation scheme selection unit 4 has a modulation scheme with more than 4 signal points (for example, 8PSK, 16PSK, etc.). Change the modulation method to.

  When the error rate of the data transmitted by the modulation method selected by the modulation method selection unit 4 is larger than a predetermined value, the modulation method selection unit 4 determines that the modulation method has a smaller error rate (that is, a lower C / N ratio). May be selected again.

  Further, the mobile communication device 100 and the ground device 400 may communicate via a relay device. Either a wireless connection, a priority connection, or both may be used between the relay device and the ground device 400.

  Note that the modulation scheme selection unit 4 of the mobile communication apparatus 100 selects the uplink and downlink modulation schemes with reference to the modulation scheme selection history for the preceding mobile unit 201, but the downlink modulation scheme is the ground device. If determined by 400, the modulation scheme selection unit 4 may select the modulation scheme only for the uplink. In this case, the modulation scheme selection history does not have to include the modulation scheme history regarding the downlink.

<Effect>
The mobile communication apparatus 100 according to the first embodiment is a mobile communication apparatus that is mounted on the mobile body 101 and communicates with the ground apparatus 400. The mobile communication apparatus 100 includes the modulation method selection history acquisition unit 2 and the mobile communication apparatus 100. , A modulation method selection unit 4 that selects a modulation method used for communication with the ground device, and a position information acquisition unit 3 that acquires a path along which the mobile body 101 moves, a current position of the mobile body 101, and a direction in which the mobile body 101 moves. The modulation scheme selection history acquisition unit 2 includes at least one preceding moving body that moves ahead of the moving body 101 in the same direction as the moving path of the moving body 101 on the same path as the moving path of the moving body 101. The modulation method selection history for 201 is acquired, and the modulation method selection history for the preceding mobile body 201 is changed to which position on the route the mobile communication device mounted on the preceding mobile body 201 is. This is a history indicating whether the method is used for communication with the ground device 400, and the modulation method selection unit 4 refers to the modulation method selection history related to at least one preceding mobile body 201 acquired by the modulation method selection history acquisition unit 2. Then, the modulation method used by the preceding moving body 201 is selected at a position corresponding to the current position of the moving body 101.

  Further, the communication method of the mobile communication device 100 is a communication method of a mobile communication device that is mounted on the mobile object 101 and communicates with the ground device 400, and (a) a route on which the mobile object 101 moves, the mobile object A step of acquiring a current position of 101 and a direction in which the moving body 101 moves; and (b) moving ahead of the moving body 101 in the same direction as the direction in which the moving body 101 moves in the same path as the path in which the moving body 101 moves. Obtaining a modulation method selection history relating to at least one preceding mobile body 201, wherein the modulation method selection history relating to the preceding mobile body 201 indicates which mobile communication device mounted on the preceding mobile body 201 is on the path. This is a history indicating which modulation method is used for communication with the ground device 400 at the position, and (c) the modulation method selection history for at least one preceding moving body is referred to, Further comprising the step of selecting a modulation scheme used in the prior mobile unit 201 at a position corresponding to the current position of the body 101.

  Mobile communication apparatus 100 according to the first embodiment acquires a modulation scheme selection history related to a preceding mobile body, and refers to the history to select a modulation scheme used for communication with ground device 400. This increases the possibility of selecting an appropriate modulation scheme with few transmission errors. Accordingly, it is possible to efficiently communicate by reducing the time required to search for an appropriate modulation method and the time required to retransmit data in which an error has occurred by changing the modulation method.

  Further, in mobile communication device 100 according to the first embodiment, modulation scheme selection history regarding at least one preceding mobile body 201 is stored in ground device 400, and modulation scheme selection history acquisition unit 2 communicates with ground device 400. The modulation method selection history relating to at least one preceding moving body 201 is acquired via.

  Therefore, the mobile communication device 100 can acquire the modulation method selection history related to the preceding mobile body 201 when transmitting / receiving data to / from the ground device 400.

  Also, in the mobile communication device 100 according to the first embodiment, when the transmission capacity of the modulation scheme selected by the modulation scheme selection section 4 is less than or equal to a predetermined value, the modulation scheme selection section 4 has a transmission capacity higher than the predetermined value. A larger modulation scheme may be selected again.

  Therefore, in the mobile communication device 100, it is possible to improve the transmission capacity of communication with the ground device 400 by reselecting a modulation method having a larger transmission capacity than the modulation method used by the preceding mobile body 201. .

<Embodiment 2>
FIG. 5 is a diagram showing the configuration of the mobile communication system in the second embodiment. Since the configuration of mobile communication apparatus 100 in the second embodiment is the same as that in the first embodiment (FIG. 1), description thereof is omitted.

  In the first embodiment, the modulation scheme selection history acquisition unit 2 of the mobile communication device 100 acquires the modulation scheme selection history regarding the preceding mobile unit 201 from the ground device 400. On the other hand, in the second embodiment, as shown in FIG. 5, the modulation scheme selection history acquisition unit 2 of the mobile communication device 100 directly selects the modulation scheme for the preceding mobile unit 201 by communicating directly with the preceding mobile unit 201. Get history.

  Note that. The communication between the mobile communication device 100 and the preceding mobile body 201 may use the same wireless method as the communication with the ground device 400. Alternatively, another wireless method including modulation method information, position information, and route information may be used.

  Moreover, the mobile communication device 100 may always transmit radio waves for mobile communication. Alternatively, in response to an instruction to perform communication between mobile units from the ground device 400, direct communication with the preceding mobile unit 201 may be performed.

  Further, the ground device 400 acquires the position information of the moving body 101 and the preceding moving body 201, determines whether the moving body 101 and the preceding moving body 201 can directly communicate, and notifies the moving body 101 of the determination result. May be. The mobile body 101 may directly communicate with the preceding mobile body 201 according to the determination result notified from the ground device 400.

  In addition, first, the mobile unit 101 tries to communicate directly with the preceding mobile unit 201. When the mobile unit 101 cannot directly communicate with the preceding mobile unit 201, the mobile unit 101 communicates with the ground device 400 in the same manner as in the first embodiment. A modulation method selection history related to may be acquired.

<Effect>
In mobile communication apparatus 100 according to the first embodiment, modulation scheme selection history acquisition unit 2 acquires modulation scheme selection history related to at least one preceding mobile body 201 by directly communicating with preceding mobile body 201.

  Accordingly, the mobile communication device 100 can acquire the modulation method selection history related to the preceding mobile body 201 by directly communicating with the preceding mobile body 201 even when data cannot be transmitted / received to / from the ground device 400. It is.

  Further, in mobile communication device 100 according to the first embodiment, the modulation scheme selection history regarding at least one preceding mobile body 201 is stored in ground device 400, and modulation scheme selection history acquisition unit 2 is directly connected to preceding mobile body 201. When communication is not possible, a modulation scheme selection history regarding at least one preceding moving body 201 may be acquired by communicating with the ground device 400.

  Therefore, even if the distance between the mobile communication device 100 and the preceding mobile body 201 is long, or there is an obstacle between the mobile communication device 100 and the preceding mobile body 201, the movement It is possible for the body communication device 100 to acquire the modulation method selection history related to the preceding mobile body 201 by communicating with the ground device 400.

<Embodiment 3>
FIG. 6 is a diagram showing the configuration of the mobile communication system in the third embodiment. Since the configuration of mobile communication apparatus 100 in the third embodiment is the same as that in the first embodiment (FIG. 1), description thereof is omitted.

  As shown in FIG. 6, a plurality of preceding moving bodies 202, 203, and 204 move in the same direction as the moving direction of the moving body 101 on the same path as the moving path of the moving body 101 on which the mobile communication device 100 is mounted. Assume that the body 101 is moving ahead of the body 101.

  In the third embodiment, the modulation scheme selection history acquisition unit 2 of the mobile communication device 100 acquires the modulation scheme selection history for a plurality of preceding mobile units 202, 203, and 204. In the third embodiment, the modulation scheme selection history acquisition unit 2 may acquire the modulation scheme selection history via the ground device 400 as described in the first embodiment, or in the second embodiment. As described above, the modulation method selection history may be acquired by direct communication with the preceding mobile body.

  The modulation scheme selection unit 4 of the mobile communication device 100 refers to the plurality of modulation scheme selection histories R202, R203, R204 regarding the plurality of preceding mobile units 202, 203, 204, and corresponds to the current position of the mobile unit 101. The modulation scheme used most frequently in the plurality of preceding mobile bodies 202, 203, 204 is selected.

  Referring to the modulation scheme selection history R202 of the preceding mobile unit 202 in FIG. 6, the modulation scheme used by the preceding mobile unit 202 at the position corresponding to the current position of the mobile unit 101 is scheme D on the uplink, and the downlink The method B in FIG. Also, referring to the modulation scheme selection history R203 of the preceding mobile unit 203 in FIG. 6, the modulation scheme used by the preceding mobile unit 203 at the position corresponding to the current position of the mobile unit 101 is scheme D on the uplink, Method B in the downlink. Further, referring to the modulation scheme selection history R204 of the preceding mobile unit 204 in FIG. 6, the modulation scheme used by the preceding mobile unit 204 at the position corresponding to the current position of the mobile unit 101 is scheme C in the uplink, Method B in the downlink. Therefore, the modulation scheme selection unit 4 of the mobile communication device 100 selects the modulation scheme D on the uplink and selects the modulation scheme B on the downlink.

  Then, the transmission / reception unit 1 of the mobile communication device 100 communicates with the ground device 400 using the modulation method selected by the modulation method selection unit 4.

  When the transmission capacity of the modulation scheme selected by the modulation scheme selection unit 4 is less than or equal to a predetermined value, the modulation scheme selection unit 4 may reselect a modulation scheme having a transmission capacity larger than the predetermined value.

  Further, when the error rate of data transmitted by the modulation scheme selected by the modulation scheme selection unit 4 is larger than a predetermined value, the modulation scheme selection unit 4 may reselect a modulation scheme having a smaller error rate.

<Effect>
In mobile communication apparatus 100 according to the third embodiment, modulation scheme history acquisition unit 2 acquires a plurality of modulation scheme selection histories related to a plurality of preceding mobile units 202, 203, and 204.

  Therefore, when the mobile communication device 100 acquires a plurality of modulation scheme selection histories for a plurality of preceding mobile units 202, 203, and 204, the modulation scheme selection unit 4 selects a modulation scheme based on more information. Is possible.

  In mobile communication apparatus 100 according to the third embodiment, modulation scheme selecting section 4 refers to a plurality of modulation scheme selection histories related to a plurality of preceding mobile bodies 202, 203, 204, and present position of mobile body 101. The modulation scheme that is most frequently used by a plurality of preceding moving bodies at the position corresponding to is selected.

  Therefore, there is a possibility that the modulation scheme selection unit 4 of the mobile communication device 100 can select a more suitable modulation scheme with fewer transmission errors by selecting the modulation scheme that is most frequently used by a plurality of preceding mobile units. Get higher. Therefore, the mobile communication device 100 can communicate with the ground device 400 more efficiently.

<Embodiment 4>
<Configuration>
FIG. 7 is a diagram showing a configuration of mobile communication apparatus 100A in the fourth embodiment. FIG. 8 is a diagram for explaining the operation of the mobile communication device 100A. As in Embodiments 1 to 3, mobile communication device 100A is mounted on mobile body 101.

  The mobile communication device 100A according to the fourth embodiment further includes a modulation method previous selection history storage unit 5 as compared with the mobile communication device 100 (FIG. 1) according to the first embodiment. The modulation method previous selection history storage unit 5 stores a modulation method previous selection history related to the moving body 101. The modulation method previous selection history is the modulation method used by the moving body 101 when the moving body 101 moved the same time in the same direction as the moving direction of the moving body 101 on the same route as the moving body 101 moves. It is history of.

<Operation>
In FIG. 8, a moving body 101 indicated by a solid line indicates the current position of the moving body. A moving body 101L indicated by a broken line indicates the same moving body as the moving body 101 that moved the same route last time. A history R101L in FIG. 8 indicates a modulation scheme used in the moving body 101L indicated by a broken line.

  The modulation scheme selection history acquisition unit 2 of the mobile communication device 100A according to the fourth embodiment first attempts to acquire the modulation scheme selection history regarding the preceding mobile unit as described in the first to third embodiments. As a result, when no modulation method selection history regarding the preceding moving body can be acquired, the modulation method selection unit 4 refers to the modulation method previous selection history storage unit 5 and corresponds to the current position of the moving body 101. The modulation method used by the moving body 101 during the previous movement is selected.

  Referring to the modulation method selection history R101L of the moving body 101L in FIG. 8, the modulation method used by the moving body 101L (that is, the same moving body as the moving body 101) at the previous movement at the position corresponding to the current position of the moving body 101. Is scheme C on the uplink and scheme B on the downlink.

  Therefore, the modulation scheme selection unit 4 of the mobile communication device 100A selects the modulation scheme C on the uplink and selects the modulation scheme B on the downlink.

<Effect>
The mobile communication device 100A according to the fourth embodiment further includes a modulation method previous selection history storage unit 5. The modulation method previous selection history storage unit 5 stores a modulation method previous selection history related to the mobile body 101, and moves. The previous selection history of the modulation method related to the body 101 indicates that the moving body 101 is on the path when the moving body 101 has moved the same path as the moving path of the moving body 101 in the same direction as the moving body 101. When the modulation scheme selection history acquisition unit 2 is unable to acquire any modulation scheme selection history regarding at least one preceding mobile body. The modulation method selection unit 4 refers to the modulation method previous selection history storage unit 5 and is used by the moving body 101 during the previous movement at a position corresponding to the current position of the moving body 101. To select the modulation scheme.

  Therefore, the mobile communication device 100A according to the fourth embodiment can refer to the history of the modulation scheme used by itself during the previous movement, and therefore cannot acquire any modulation scheme selection history regarding the preceding mobile body. Even if it exists, possibility that the suitable modulation system with few transmission errors can be selected becomes high. Therefore, the mobile communication device 100A can efficiently communicate with the ground device 400.

<Embodiment 5>
<Configuration>
FIG. 9 is a diagram showing a configuration of mobile communication apparatus 100B in the fifth embodiment. FIG. 10 is a diagram showing the configuration of the mobile communication system in the fifth embodiment. In the fifth embodiment, mobile communication device 100B is mounted on each of mobile body 101, preceding mobile body 102, and subsequent mobile body 103.

  As shown in FIG. 10, in the fifth embodiment, the preceding moving body 102 moves ahead of the moving body 101 in the same direction as the moving body 101 along the same path as the moving body 101 moves. Assuming that Further, it is assumed that the subsequent moving body 103 moves from the rear of the moving body 101 in the same direction as the moving body 101 moves along the same route as the moving body 101 moves.

  Mobile communication apparatus 100B in the fifth embodiment further includes modulation scheme selection history storage section 7 and modulation scheme selection history notification section 6 as compared with mobile communication apparatus 100 (FIG. 1) in the first embodiment. .

  The modulation method selection history storage unit 7 of the mobile communication device 100B mounted on the mobile object 101 stores a modulation method selection history related to the mobile object 101. The modulation method selection history related to the mobile object 101 is a history indicating which modulation method used by the mobile communication device 100B mounted on the mobile object 101 for communication with the ground device 400 at which position on the route.

  Also, the modulation method selection history storage unit 7 of the mobile communication device 100B mounted on the preceding mobile body 102 stores the modulation method selection history related to the preceding mobile body 102. Also, the modulation method selection history storage unit 7 of the mobile communication device 100B mounted on the subsequent mobile body 103 stores the modulation method selection history related to the subsequent mobile body 103.

  The modulation method selection history notifying unit 6 of the mobile communication device 100B mounted on the moving body 101 causes the subsequent moving body 103 to acquire a modulation method selection history related to the moving body 101. Similarly, the modulation method selection history notifying unit 6 of the mobile communication device 100B mounted on the preceding mobile body 102 causes the mobile body 101 to acquire a modulation method selection history related to the preceding mobile body 102. Further, the modulation scheme selection history notifying unit 6 of the mobile communication device 100B mounted on the subsequent mobile body 103 causes a mobile body (not shown) following the subsequent mobile body 103 to acquire a modulation scheme selection history related to the subsequent mobile body 103. .

<Operation>
FIG. 11 is a flowchart showing the operation of the mobile communication device 100B. Below, the mobile communication apparatus 100B mounted on the mobile body 101 will be described. The operation in which mobile communication apparatus 100B mounted on mobile body 101 acquires modulation scheme selection history 102R related to preceding mobile body 102 and selects a modulation scheme (steps S201 to S204 in FIG. 11) is described in the first embodiment. Since this is the same as the operation described in (Steps S101 to S104 in FIG. 4), description thereof is omitted.

  After step S204 in FIG. 11, the modulation scheme selection history notifying unit 6 of the mobile communication device 100B mounted on the mobile unit 101 causes the subsequent mobile unit 103 to acquire its own modulation scheme selection history R101 (step in FIG. 11). S205).

  In step S205, the modulation scheme selection history notifying unit 6 of the mobile communication device 100B mounted on the mobile unit 101 causes the subsequent mobile unit 103 to acquire its modulation scheme selection history R101 via the ground device 400.

  Also, in step S205, the modulation scheme selection history notifying unit 6 of the mobile communication device 100B mounted on the mobile unit 101 transmits the own modulation scheme selection history R101 to the subsequent mobile unit 103 through direct communication with the subsequent mobile unit 103. May be acquired.

  The modulation scheme selection unit 4 of the mobile communication device 100B mounted on the subsequent mobile unit 103 refers to the modulation scheme selection history R101 related to the mobile unit 101, and moves the mobile unit 101 at a position corresponding to the current position of the subsequent mobile unit 103. Select the modulation method used in.

  Referring to history R101 in FIG. 10, the modulation scheme used by mobile unit 101 at a position corresponding to the current position of subsequent mobile unit 103 is scheme D on the uplink and scheme B on the downlink. Therefore, the modulation scheme selection unit 4 of the mobile communication device 100B mounted on the subsequent mobile unit 103 selects the modulation scheme D on the uplink and selects the modulation scheme B on the downlink.

  Then, the transmission / reception unit 1 of the mobile communication device 100B mounted on the subsequent mobile unit 103 communicates with the ground device 400 using the modulation scheme selected by the modulation scheme selection unit 4.

  The operation of the mobile communication device 100B mounted on the mobile body 101 has been mainly described above. However, the mobile communication device 100B mounted on the preceding mobile body 102 and the mobile communication device mounted on the subsequent mobile body 103 are described. The same operation is performed for 100B.

<Effect>
Mobile communication device 100B according to Embodiment 5 further includes a modulation scheme selection history storage unit 7 and a modulation scheme selection history notification unit 6. The modulation scheme selection history storage unit 7 includes a modulation relating to the mobile unit 101. The method selection history is stored, and the modulation method selection history related to the mobile unit 101 indicates which modulation method used by the mobile communication device 100B mounted on the mobile unit 101 for communication with the ground device 400 at which position on the route. The modulation method selection history notifying unit 6 sends the same path as the moving path of the moving body 101 to the subsequent moving body 103 that moves from the rear of the moving body 101 in the same direction as the moving body 101 moves. Then, a modulation method selection history regarding the moving body 101 is acquired.

  Modulation scheme selection history notifying section 6 of mobile communication apparatus 100B mounted on mobile body 101 in the fifth embodiment causes subsequent mobile body 103 to acquire a modulation scheme selection history related to mobile body 101. Therefore, since the succeeding mobile unit 103 can select a modulation method used for communication with the ground device 400 with reference to the modulation method selection history related to the mobile unit 101, there is a high possibility that an appropriate modulation method with few transmission errors can be selected. Become. Therefore, the subsequent mobile unit 103 can efficiently communicate by reducing the time required to search for an appropriate modulation method and the time required to retransmit data in which an error has occurred by changing the modulation method. Is possible.

  Further, in mobile communication apparatus 100B in the fifth embodiment, modulation scheme selection history notifying section 6 may cause subsequent mobile body 103 to acquire a modulation scheme selection history related to mobile body 101 via ground apparatus 400. Good.

  Therefore, the mobile communication device 100B mounted on the subsequent mobile body 103 can acquire the modulation method selection history related to the mobile body 101 when transmitting / receiving data to / from the ground device 400.

  Further, in mobile communication apparatus 100B in the fifth embodiment, modulation scheme selection history notifying unit 6 causes subsequent mobile body 103 to acquire a modulation scheme selection history related to mobile body 101 by direct communication with subsequent mobile body 103. .

  Therefore, even if the mobile communication device 100B mounted on the subsequent mobile body 103 cannot transmit / receive data to / from the ground device 400, the modulation method selection history related to the mobile body 101 can be obtained by directly communicating with the mobile body 101. Is possible to get.

  The mobile communication system according to Embodiment 5 includes a plurality of mobile communication devices 100B, and the plurality of mobile communication devices 100B includes a plurality of mobiles (that is, mobile 101, preceding mobile 102, and subsequent mobile). 103), and a plurality of moving bodies move in the same direction on the same route.

  In the mobile communication system according to Embodiment 5, the mobile communication device 100B mounted on the mobile 101 acquires an appropriate modulation scheme by acquiring the modulation scheme selection history for the preceding mobile unit 102 and selecting the modulation scheme. Can be selected. Furthermore, the mobile communication device 100B mounted on the subsequent mobile unit 103 can select an appropriate modulation method by acquiring a modulation method selection history related to the mobile unit 101 and selecting a modulation method. As described above, by mounting the mobile communication device 100B on each of a plurality of mobile bodies that move in the same direction on the same route, subsequent mobile bodies can use the modulation method selection history of the preceding mobile body. Therefore, each mobile body can efficiently communicate with the ground device 400.

  In Embodiments 1 to 5 described above, the mobile body on which mobile communication devices 100, 100A, and 100B are mounted is described as a train, but the mobile body is not limited to a train. The moving body may be, for example, an automobile or an aircraft. It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

  DESCRIPTION OF SYMBOLS 1 Transmission / reception part, 2 Modulation system selection log | history acquisition part, 3 Position information acquisition part, 4 Modulation system selection part, 5 Modulation system last selection log | history storage part, 6 Modulation system selection log | history notification part, 7 Modulation system selection log | history storage part, 100 Mobile communication device, 101, 101L Mobile body, 102, 201, 202, 203, 204 Preceding mobile body, 103 Subsequent mobile body, 400 Ground device.

Claims (13)

A mobile communication device mounted on a mobile body and communicating with a ground device,
The mobile communication device is:
A modulation method selection history acquisition unit;
A modulation method selection unit for selecting a modulation method used for communication with the ground device;
A position information acquisition unit that acquires a path along which the moving body moves, a current position of the moving body, and a direction in which the moving body moves;
With
The modulation method selection history acquisition unit stores a modulation method selection history related to at least one preceding moving body that moves ahead of the moving body in the same direction as the moving body on the same route as the path on which the moving body moves. Acquired,
The modulation method selection history related to the preceding moving body is a history indicating which modulation method is used for communication with the ground device at which position on the route by the mobile communication device mounted on the preceding moving body. Yes,
The modulation scheme selection unit refers to the modulation scheme selection history related to at least one preceding moving body acquired by the modulation scheme selection history acquisition unit, and moves the preceding movement at a position corresponding to the current position of the moving body. Select the modulation method used in the body,
Mobile communication device. The modulation scheme selection history for at least one preceding mobile is stored in the ground unit;
The modulation scheme selection history acquisition unit acquires the modulation scheme selection history related to at least one preceding moving body via communication with the ground device.
The mobile communication device according to claim 1. The modulation scheme selection history acquisition unit acquires the modulation scheme selection history related to at least one preceding mobile body by directly communicating with the preceding mobile body.
The mobile communication device according to claim 1. The modulation scheme selection history for at least one preceding mobile is stored in the ground unit;
The modulation scheme selection history acquisition unit acquires the modulation scheme selection history related to at least one preceding mobile body by communicating with the ground device when direct communication with the preceding mobile body is impossible.
The mobile communication device according to claim 3. The modulation scheme selection history acquisition unit acquires a plurality of modulation scheme selection histories related to a plurality of the preceding moving bodies.
The mobile communication device according to any one of claims 1 to 4. The modulation method selection unit refers to a plurality of modulation method selection histories related to a plurality of the preceding moving bodies, and performs modulation most frequently used by the plurality of preceding moving bodies at a position corresponding to the current position of the moving body. Select a method,
The mobile communication device according to claim 5. When the transmission capacity of the modulation scheme selected by the modulation scheme selection unit is a predetermined value or less, the modulation scheme selection unit reselects a modulation scheme having a transmission capacity larger than the predetermined value.
The mobile communication device according to any one of claims 1 to 6. Further comprising a modulation method last selection history storage unit,
In the modulation scheme previous selection history storage unit, a modulation scheme previous selection history related to the moving body is stored,
The modulation method previous selection history for the moving body is the same as the path the moving body is moving, and when the moving body has moved in the same direction as the moving body, the moving body A history indicating which modulation method is used for communication with the ground device at which position on the route;
When the modulation scheme selection history acquisition unit cannot acquire at least one modulation scheme selection history related to at least one preceding moving body, the modulation scheme selection unit refers to the modulation scheme previous selection history storage unit, and Select the modulation method used by the moving body during the previous movement at the position corresponding to the current position of the moving body,
The mobile communication device according to any one of claims 1 to 7. A modulation method selection history storage unit;
A modulation method selection history notification unit;
Further comprising
The modulation method selection history storage unit stores a modulation method selection history related to the moving object,
The modulation method selection history related to the mobile object is a history indicating which modulation method used by the mobile communication device mounted on the mobile object for communication with the ground device at which position on the route. ,
The modulation method selection history notifying unit transmits the modulation relating to the moving body to a subsequent moving body that moves after the moving body in the same direction as the moving body on the same path as the path on which the moving body moves. Get method selection history,
The mobile communication device according to any one of claims 1 to 8. The modulation method selection history notifying unit causes the subsequent moving body to acquire the modulation method selection history related to the moving body via the ground device.
The mobile communication device according to claim 9. The modulation method selection history notifying unit causes the subsequent moving body to acquire the modulation method selection history related to the moving body through direct communication with the subsequent moving body.
The mobile communication device according to claim 9. A plurality of mobile communication devices according to any one of claims 1 to 11,
The plurality of mobile communication devices are mounted on each of the plurality of mobile bodies,
The plurality of moving bodies move in the same direction along the same path;
Mobile communication system. A communication method of a mobile communication device that is mounted on a mobile and communicates with a ground device,
(A) obtaining a path along which the moving body moves, a current position of the moving body and a direction in which the moving body moves;
(B) obtaining a modulation scheme selection history for at least one preceding moving body that moves ahead of the moving body in the same direction as the moving body on the same path as the moving path of the moving body;
With
The modulation method selection history related to the preceding moving body is a history indicating which modulation method is used for communication with the ground device at which position on the route by the mobile communication device mounted on the preceding moving body. Yes,
(C) referring to the modulation scheme selection history for at least one preceding moving body, further comprising the step of selecting a modulation scheme used by the preceding moving body at a position corresponding to the current position of the moving body;
A communication method for a mobile communication device.

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