JP2019054645A - Train communication system - Google Patents

Abstract

To provide a technique for lowering manufacturing cost, while taking into consideration attenuation in millimeter wave communication, in a train communication system.SOLUTION: A train communication system on a technique disclosed in the present application specification, comprises a plurality of base station devices (20, 20A and 12) arranged along a railway track, a central device (11) communicable with each of the base station devices and an on-railway vehicle radio device (30) which is mounted on a train traveling on the railway track and can communicate with the plurality of base station devices, the on-railway vehicle radio device performs communication with the base station devices using a first radio wave and changes over the communication with the base station devices to the communication using a second radio wave when intensity of a received first radio wave received from the base station devices is smaller than a predetermined threshold value.SELECTED DRAWING: Figure 1

Description

  The technology disclosed in the present specification relates to a train communication system.

  In recent years, the speed of communication means has been increasing, and long term evolution (LTE) and world wide interoperability for microwave access (WiMAX) 2+ have become widespread, and the fifth generation mobile phone (5G) is about to be put into practical use. Near at hand.

  Also in the train environment, in recent years, IT has been advanced, and in addition to conventional train radio, that is, operation commands, as a passenger system service, an Internet connection service using a wireless LAN has been developed mainly for Shinkansen or conventional express trains ( For example, see Patent Document 1).

  In addition, IoT has been put to practical use as an operation service, and information on various sensors mounted on the vehicle or vehicle logs is transferred to the ground supervisor, and information such as failure is quickly grasped and maintained. Etc. Similarly, systems that support ECO driving by transferring vehicle operating conditions, for example, vehicle speed or braking status, to ground supervisors have been put into practical use.

  In the future, ground-to-vehicle communication in trains is expected to have a larger capacity, but the frequency bands of the very high frequency (VHF) waveband and the ultra high frequency (UHF) wave band that have been used by conventional train radio are in the band. There are aspects that are narrow and difficult to increase in capacity. On the other hand, it is considered that a train radio system using a millimeter wave having a relatively free frequency will spread in the future.

JP 2002-344478 A

  However, millimeter waves are highly linear and have a large amount of attenuation due to the nature of radio waves. Especially in rainy weather, millimeter waves are greatly attenuated by rainfall. Therefore, in order to perform stable millimeter wave communication, it is necessary to closely arrange base stations that transmit and receive millimeter waves.

  In addition, the communication device of the millimeter wave band is more severely designed than the wireless communication device of the VHF wave band and the UHF wave band, and high accuracy is required for the communication device, the board, and the machine work. If communication devices are arranged densely, there is a problem that the manufacturing cost of the device and system increases.

  The technology disclosed in the specification of the present application has been made in order to solve the problems described above, and in a train communication system, in order to reduce the manufacturing cost while considering attenuation of millimeter wave communication. The purpose is to provide technology.

  A first aspect of the technology disclosed in the specification of the present application is a plurality of base station devices arranged along a track, a central device capable of communicating with each of the base station devices, and a train traveling on the track. And an on-board wireless device that is communicable with a plurality of the base station devices, wherein the on-board wireless device is between at least one of the base station devices. , Communication using a first radio wave that is a millimeter wave is possible, and the on-board wireless device communicates the first radio wave between at least one of the base station devices. Communication using a second radio wave having a longer wavelength than the base station device, the on-board wireless device performs communication using the first radio wave with each of the base station devices, and the base station The reception intensity of the first radio wave received from the station device is already available. Is smaller than a defined threshold, the communication between the base station apparatus switches the communication using the second radio wave.

  A first aspect of the technology disclosed in the specification of the present application is a plurality of base station devices arranged along a track, a central device capable of communicating with each of the base station devices, and a train traveling on the track. And an on-board wireless device that is communicable with a plurality of the base station devices, wherein the on-board wireless device is between at least one of the base station devices. , Communication using a first radio wave that is a millimeter wave is possible, and the on-board wireless device communicates the first radio wave between at least one of the base station devices. Communication using a second radio wave having a longer wavelength than the base station device, the on-board wireless device performs communication using the first radio wave with each of the base station devices, and the base station The reception intensity of the first radio wave received from the station device is already available. Is smaller than a defined threshold, the communication between the base station apparatus, in which switching to communication using the second radio wave. According to such a configuration, even when the millimeter wave communication becomes unstable due to a reduction in the millimeter wave communication area on the track in rainy weather or the like, UHF wave communication that is not easily affected by rain attenuation, etc. By switching to, the communication area in the entire track can be maintained.

  The objectives, features, aspects, and advantages of the technology disclosed in this specification will become more apparent from the detailed description and the accompanying drawings provided below.

It is a figure which illustrates schematically the composition for realizing a train communication system about an embodiment. It is a functional block diagram which illustrates notionally the composition of the onboard radio equipment carried in a train about an embodiment. It is a figure which illustrates the structure of the train communication system regarding embodiment with an actual circuit design. It is a figure which illustrates arrangement | positioning of a millimeter wave base station apparatus when a track | line is curving. It is a figure which illustrates arrangement | positioning of the mixed base station apparatus when a track | line is curving. It is a figure which illustrates arrangement | positioning of a millimeter wave base station apparatus in case there exists a height difference in a track | line. It is a figure which illustrates arrangement | positioning of a mixed base station apparatus in case there exists a height difference in a track | line. It is a figure which illustrates arrangement | positioning of the millimeter wave base station apparatus in a train communication system. It is a figure which illustrates the communication area at the time of fine weather formed by the several millimeter wave base station apparatus illustrated by FIG. It is a figure which illustrates the communication area at the time of rainy weather formed by the several millimeter wave base station apparatus illustrated by FIG. It is a graph which shows the relationship between the frequency and attenuation coefficient in different precipitation. It is a figure which shows the modification of a structure of a train communication system.

  Embodiments will be described below with reference to the accompanying drawings.

  Note that the drawings are schematically shown, and the configuration is omitted or simplified as appropriate for the convenience of explanation. In addition, the mutual relationships between the sizes and positions of the configurations and the like shown in different drawings are not necessarily accurately described and can be changed as appropriate.

  Moreover, in the description shown below, the same code | symbol is attached | subjected and shown in the same component, and it is the same also about those names and functions. Therefore, detailed descriptions thereof may be omitted to avoid duplication.

  In addition, in the description described below, even if an ordinal number such as “first” or “second” is used, these terms mean that the contents of the embodiment are understood. It is used for the sake of convenience, and is not limited to the order that can be generated by these ordinal numbers.

<First Embodiment>
Hereinafter, the train communication system according to the present embodiment will be described. For convenience of explanation, first, the arrangement of the millimeter wave base station device in the train communication system and the millimeter wave communication by the millimeter wave base station device will be described.

  FIG. 8 is a diagram illustrating an arrangement of millimeter wave base station devices in a train communication system. As illustrated in FIG. 8, in the train communication system, an upstream train 16 travels on the upstream line 13, and a downstream train 15 travels on the downstream line 14, and a plurality of millimeter waves beside each rail line. A base station apparatus 12 is installed. Each millimeter wave base station apparatus 12 is a base station apparatus capable of transmitting and receiving millimeter wave radio waves.

  An optical signal is transmitted from the central apparatus 11 to each millimeter wave base station apparatus 12 via the optical fiber 17. Then, by converting the optical signal into millimeter waves (radio waves) in the millimeter wave base station apparatus 12, the central apparatus 11 performs millimeter wave communication between the up train 16 and the down train 15 that receive the millimeter waves. .

  FIG. 9 is a diagram illustrating a communication area in fine weather formed by the plurality of millimeter wave base station apparatuses 12 illustrated in FIG. 8. As illustrated in FIG. 9, the millimeter wave communication area 22 formed by the millimeter wave base station apparatus 12 overlaps with the millimeter wave communication area 22 formed by another adjacent millimeter wave base station apparatus 12, and communication is performed. The overlapping area 18 is formed.

  On the other hand, FIG. 10 is a diagram illustrating a communication area during rainy weather formed by the plurality of millimeter wave base station apparatuses 12 illustrated in FIG. As illustrated in FIG. 10, the millimeter wave communication area 22 formed by the millimeter wave base station apparatus 12 is narrower than the millimeter wave communication area 22 in fine weather illustrated in FIG. 9.

  FIG. 11 is a graph showing the relationship between frequency and attenuation coefficient at different precipitation amounts. In FIG. 11, the vertical axis represents the attenuation coefficient [dB / km], and the horizontal axis represents the frequency [GHz].

  As shown in FIG. 11, in the frequency band of 5 GHz or more, rain attenuation during rain is generally large. For example, when a 40 GHz band millimeter wave is used, the rain attenuation per km is attenuated by about 1.5 dB when the precipitation is 5 mm / h, and by about 30 dB when the precipitation is 100 mm / h. Therefore, in FIG. 10, the millimeter wave communication area 22 formed by the millimeter wave base station apparatus 12 is narrow.

  In view of the recent heavy rains in urban areas, the rain of about 70 mm / h is daily, and further global rains may cause more intense rain in the future.

  In order to perform stable millimeter wave communication, it is necessary to consider rain attenuation of about 70 mm / h in the circuit design in view of these.

  The arrangement of the millimeter wave base station apparatus 12 illustrated in FIG. 10 is an arrangement in consideration of the reduction of the millimeter wave communication area 22 in rainy weather. In this arrangement, as illustrated in FIG. The overlapping area 18 is formed. Therefore, in fine weather, the millimeter wave communication area 22 becomes excessively dense, which increases the manufacturing cost of the train communication system.

<Configuration of train communication system>
FIG. 1 is a diagram schematically illustrating a configuration for realizing a train communication system according to the present embodiment.

  As illustrated in FIG. 1, the train communication system according to the present embodiment includes a central device 11 and a plurality of mixed base station devices 20 installed along a railway line or a station.

  Each mixed base station apparatus 20 is connected to the central apparatus 11 via the optical fiber 17. The plurality of mixed base station devices 20 are arranged at intervals of several hundred meters.

  Each mixed base station apparatus 20 is a base station apparatus capable of transmitting and receiving both millimeter wave radio waves and UHF radio waves.

  The central device 11 modulates communication data and converts it into an optical signal. The central apparatus 11 transmits an optical signal to the mixed base station apparatus 20 via the optical fiber 17. The transmitted optical signal is converted into radio waves in the millimeter wave band or UHF wave band in the mixed base station apparatus 20, and is emitted toward the vehicle traveling on the track.

  The communication data includes driving instructions, information on various sensors mounted on the vehicle, vehicle logs, and operation state information such as speed or brake state. The communication data is also used for an Internet connection service as a passenger service.

  Among these, the operation command is communication data indispensable for train operation, and it is necessary to secure a communication path for transmitting the operation command regardless of when it is fine or rainy. On the other hand, information of various sensors mounted on the vehicle, vehicle logs, Internet connection services, and the like are best-effort communication data that can be finally communicated even if there is some interruption.

  In consideration of the fact that the UHF wave band has a relatively narrow frequency band and there is a side where it is difficult to increase the capacity of information, in this embodiment, for example, only operation command data essential for train operation is transmitted and received. On the other hand, considering that the millimeter wave band has a relatively wide frequency band and can increase the capacity of information, not only driving commands but also information on various sensors mounted on the vehicle, vehicle logs, and Data of Internet connection service is also transmitted and received.

  When the weather is fine, millimeter-wave radio waves originally reach the adjacent mixed base station apparatus 20. However, since the frequency band of 5 GHz or more generally has a large rain attenuation during rainy weather, it may not reach the adjacent mixed base station apparatus 20 and cannot be ignored in the circuit design.

  For example, in the case of a 40 GHz band millimeter wave, the rain attenuation per km is about 1.5 dB when the precipitation is 5 mm / h, and about 30 dB when the precipitation is 100 mm / h. Therefore, the millimeter wave communication area is like the millimeter wave communication area 22. On the other hand, since the UHF wave band is not easily affected by rain attenuation, the UHF wave communication area is like the UHF wave communication area 21.

  FIG. 2 is a functional block diagram conceptually illustrating the configuration of the on-board wireless device mounted on the train. As illustrated in FIG. 2, the on-vehicle wireless device 30 can communicate with a base station device arranged along a track. The on-vehicle wireless device 30 includes a millimeter wave wireless device 33 connected to the millimeter wave antenna 31, a UHF wave wireless device 34 connected to the UHF wave antenna 32, and a wireless switching device 40. The wireless switching device 40 includes a signal switching device 39 and a signal determination circuit 41.

  The millimeter-wave radio device 33 receives a received signal strength indication (i.e. RSSI) signal 35 and millimeter-wave communication according to a signal received by the millimeter-wave antenna 31 from a base station device arranged along the track. Data 37 is output. The millimeter wave RSSI signal 35 is input to the signal determination circuit 41 in the wireless switching device 40, and the millimeter wave communication data 37 is input to the signal switching device 39 in the wireless switching device 40.

  The UHF wave radio 34 outputs a UHF wave RSSI signal 36 and UHF wave communication data 38 in accordance with a signal received by the UHF wave antenna 32 from a base station device arranged along the track. The UHF wave RSSI signal 36 is input to a signal determination circuit 41 in the wireless switching device 40, and the UHF wave communication data 38 is input to a signal switching device 39 in the wireless switching device 40.

  The signal discrimination circuit 41 compares the millimeter wave RSSI signal 35 with the UHF wave RSSI signal 36. The signal determination circuit 41 outputs a switching signal 42 based on the comparison result between the millimeter wave RSSI signal 35 and the UHF wave RSSI signal 36, and controls the switching operation of the signal switching device 39 by the switching signal 42.

  The signal discriminating circuit 41 normally causes the signal switching device 39 to preferentially select the millimeter wave communication data 37 and causes the lower order device to transmit the communication data 43.

  On the other hand, the signal discriminating circuit 41 controls the signal switching device 39 by the switching signal 42 when the millimeter wave RSSI signal 35 input to the signal discriminating circuit 41 falls below a predetermined threshold value in rainy weather. Then, the UHF wave communication data 38 is selected by the signal switching device 39, and the communication data 43 is transmitted to the lower device.

  The on-vehicle wireless device 30 can transmit and receive a driving command, information on various sensors mounted on the vehicle, a vehicle log, and an Internet connection service using a millimeter-wave line in fine weather. In addition, the on-vehicle wireless device 30 can communicate a driving command using a UHF wave band line when the millimeter wave band line becomes unstable during rainy weather.

  It goes without saying that the same communication data is always transmitted to the mixed base station apparatus 20 installed along the track.

  FIG. 3 is a diagram illustrating the configuration of the train communication system according to the present embodiment together with the actual circuit design. In the case illustrated in FIG. 3, the millimeter wave base station devices including those installed in the mixed base station device 20 are arranged at approximately 1000 m intervals in consideration of the fine weather. On the other hand, the mixed base station apparatuses 20 are arranged at intervals of about 2000 m.

  The millimeter wave base station apparatus 12 is a base station apparatus capable of transmitting and receiving millimeter waves. The transmission power of the millimeter wave base station apparatus 12 is 15 dBm, the transmission antenna gain is 32.3 dBi, the power loss and the like are −2.5 dB, and the radiation power is 44.8 dBm. The propagation loss is -120.8 dB.

  Further, the receiving antenna gain of the millimeter wave antenna 31 in the on-vehicle wireless device 30 is 32.3 dBi, the feeding loss and the like are −2.5 dB, and the received power is −46.2 dBm. The line margin is −25.9 dB including the rainfall loss of −13.7 dB.

  The required received power is −72.1 dBm and the transmission distance is 551 m. The transmission distance without rain is about 1800 m. However, in practice, it is rare that a straight section of 1800 m continues on the track, so about 1000 m is assumed.

  On the other hand, the transmission power of the UHF wave in the mixed base station apparatus 20 is 27 dBm, the transmission antenna gain is 7 dBi, the power supply loss such as the shared device is −17 dB, and the radiation power is 17 dBm. The propagation loss is -96.7 dB.

  In addition, the receiving antenna gain of the UHF wave antenna 32 in the on-vehicle wireless device 30 is 0 dBi, the power supply loss of the shared machine etc. is −8 dB, and the received power is −87.7 dBm. The line margin is −20 dB.

  The required received power is -107.7 dBm, and the transmission distance is 4000 m. It should be noted that the transmission distance is assumed to be about 2000 m, which is half of the transmission distance because there is a shielding by buildings in urban areas.

  Since millimeter waves are highly straight and line-of-sight communication is essential, the propagation loss is calculated on the assumption of the square law (free space propagation loss).

<Second Embodiment>
A train communication system according to the present embodiment will be described. In the following description, the same components as those described in the embodiment described above are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

<Configuration of train communication system>
FIG. 4 is a diagram illustrating an arrangement of the millimeter wave base station apparatus when the track is curved. In FIG. 4, the millimeter wave communication area 22 at the time of rain is illustrated. FIG. 5 is a diagram illustrating an arrangement of the mixed base station apparatus when the track is curved. In FIG. 5, the millimeter wave communication area 22 in rainy weather and the UHF wave communication area 21 in rainy weather are illustrated.

  As illustrated in FIG. 4, when the line is curved, when trying to secure a communication area on the line only by the millimeter wave base station apparatus 12, three millimeter wave base station apparatuses 12 are arranged. There is a need.

  On the other hand, as illustrated in FIG. 5, when the mixed curve base station device 20 tries to secure a communication area on the track when the track is curved, the UHF wave communication area 21 during rainy weather is wide. For some reason, two mixed base station apparatuses 20 are required. That is, a communication area can be efficiently secured with a small number of base station apparatuses.

  FIG. 6 is a diagram illustrating an arrangement of the millimeter wave base station apparatus when there is a height difference in the line. In FIG. 6, the millimeter wave communication area 22 in rainy weather is illustrated. FIG. 7 is a diagram illustrating the arrangement of mixed base station apparatuses when there is a difference in height between lines. In FIG. 7, the millimeter wave communication area 22 in rainy weather and the UHF wave communication area 21 in rainy weather are illustrated.

  As illustrated in FIG. 6, when the communication area is to be secured on the line only by the millimeter wave base station apparatus 12 when there is a height difference on the line, three millimeter wave base station apparatuses 12 are arranged. There is a need.

  On the other hand, as illustrated in FIG. 7, when the mixed base station apparatus 20 tries to secure a communication area on the line when there is a difference in height on the line, the UHF wave communication area 21 in the rainy weather is also wide. As a result, two mixed base station apparatuses 20 are required. That is, a communication area can be efficiently secured with a small number of base station apparatuses.

  In the on-vehicle wireless device 30, the millimeter wave RSSI signal 35 and the UHF wave output from the millimeter wave radio device 33 are not considered without considering that the line is curved and that the line has a height difference. Based on the UHF wave RSSI signal 36 output from the radio device 34, UHF wave communication may be performed when the millimeter wave signal intensity falls below a predetermined threshold.

<Third Embodiment>
A train communication system according to the present embodiment will be described. In the following description, the same components as those described in the embodiment described above are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.

<Configuration of train communication system>
As exemplified in the first embodiment and the second embodiment, since the operation command included in the communication data is transmitted and received in both the millimeter wave band and the UHF wave band, the hardware and communication Both roads have a redundant configuration. In particular, when the millimeter wave base station device 12 becomes unable to communicate due to a failure or the like, or when the mixed base station device 20 becomes unable to communicate with millimeter waves, an operation command that is essential for train operation in the UHF wave band. It is possible to secure a communication path.

  Note that the failure detection of the millimeter wave base station apparatus 12 is performed using the millimeter wave RSSI signal 35 and the UHF wave RSSI signal 36 in FIG. Specifically, when the reception intensity of the millimeter wave RSSI signal 35 falls below a predetermined threshold, it is detected that the millimeter wave base station apparatus 12 has failed.

<About the effects produced by the embodiment described above>
Next, effects produced by the embodiment described above will be exemplified. In the following description, the effect is described based on the specific configuration exemplified in the above-described embodiment, but is exemplified in the present specification within a range in which the same effect occurs. Other specific configurations may be substituted.

  Further, the replacement may be performed across a plurality of embodiments. In other words, the configurations exemplified in different embodiments may be combined to produce the same effect.

  According to the embodiment described above, the train communication system includes a plurality of base station devices arranged along the track, a central device 11 capable of communicating with each base station device, and a train traveling on the track. And an on-vehicle wireless device 30 mounted on the vehicle. Here, the base station apparatus corresponds to at least one of the mixed base station apparatus 20 and the millimeter wave base station apparatus 12, for example. The on-vehicle wireless device 30 can communicate with a plurality of base station devices. In addition, the on-board wireless device 30 can perform communication using millimeter waves between at least one base station device among a plurality of base station devices. In addition, the on-vehicle wireless device 30 can perform communication using a second radio wave having a longer wavelength than the millimeter wave between at least one base station device among the plurality of base station devices. Here, the second radio wave is, for example, a UHF wave. The on-vehicle wireless device 30 performs communication using millimeter waves with each base station device, and the reception intensity of the millimeter waves received from the base station device is smaller than a predetermined threshold value. In addition, the communication with the base station apparatus is switched to the communication using the UHF wave.

  According to such a configuration, UHF wave communication that is not easily affected by rain attenuation even when the millimeter wave communication becomes unstable due to the reduction of the millimeter wave communication area 22 on the track in rainy weather or the like. By switching to the above, the communication area in the entire track can be maintained.

  Compared to a millimeter wave communication device, a UHF wave communication device is cheaper and easier to design and work. Therefore, it is better to arrange a UHF wave communication device for switching communication in the rain than to arrange a millimeter wave communication device densely considering the reduction of the millimeter wave communication area 22 in rainy weather. System manufacturing costs can be reduced.

  In the above train communication system, the millimeter wave line and the UHF wave line have a redundant configuration, so that a high quality communication path is provided.

  In addition, millimeter wave communication is unstable not only when it rains but also when the track is curved or when there is a difference in elevation due to the strong nature of millimeter wave. become. Even in such a case, according to the train communication system described above, the communication area in the entire track can be maintained.

  Other configurations exemplified in the present specification other than these configurations can be omitted as appropriate. That is, if at least these configurations are provided, the effects described above can be produced.

  However, when at least one of the other configurations exemplified in the present specification is appropriately added to the configuration described above, that is, as exemplified in the present specification that has not been referred to as the configuration described above. Even when other configurations are added as appropriate, similar effects can be produced.

  Further, according to the embodiment described above, the plurality of base station apparatuses include the mixed base station apparatus 20 that can transmit and receive both millimeter waves and UHF waves. According to such a configuration, the millimeter wave communication and the communication using the UHF wave can be switched by using one base station device, so that the configuration of the train communication system can be reduced. Manufacturing cost can be suppressed.

  Further, according to the embodiment described above, the plurality of base station apparatuses include the millimeter wave base station apparatus 12 capable of transmitting and receiving millimeter waves. According to such a configuration, when millimeter wave communication is performed in fine weather by the millimeter wave base station device 12 and the mixed base station device 20, the overlap of the millimeter wave communication area 22 on the line is suppressed, and in the rainy weather. When performing UHF wave communication, the mixed base station apparatus 20 can secure the UHF wave communication area 21 over the entire line.

  Further, according to the embodiment described above, the on-board wireless device 30 uses the millimeter wave when the millimeter wave base station device 12 becomes unable to communicate or with the mixed base station device 20. When communication that has been performed becomes impossible, communication with the base station apparatus is switched to communication using UHF waves. According to such a configuration, since the millimeter wave communication line and the UHF wave communication line function as redundant lines, a high-quality communication path can be provided.

  Further, according to the embodiment described above, the on-vehicle wireless device 30 transmits and receives communication data including a driving command when performing communication using UHF waves with each base station device. According to such a configuration, even if millimeter wave communication becomes unstable, a communication path for transmitting an operation command, which is communication data essential for train operation, by switching to UHF wave communication. Can be secured.

<Modifications in Embodiments Described above>
FIG. 12 is a diagram illustrating a modification of the configuration of the train communication system. As shown in FIG. 12, the train communication system includes a central device 11 and a plurality of mixed base station devices 20A installed along a track or at a station or the like.

  The mixed base station device 20A is a base station device that can radiate radio waves in both the upward and downward directions of the track.

  In this way, it is possible to assume changes in the arrangement conditions of a plurality of base station devices.

  In the embodiment described above, the material, material, dimension, shape, relative arrangement relationship, or implementation condition of each component may be described, but these are examples in all aspects. Thus, it is not limited to those described in this specification.

  Accordingly, countless variations and equivalents not illustrated are envisioned within the scope of the technology disclosed in this specification. For example, when deforming, adding or omitting at least one component, extracting at least one component in at least one embodiment, and combining with at least one component in another embodiment Is included.

  In addition, as long as no contradiction arises, “one or more” components described as being provided with “one” in the embodiment described above may be provided.

  Further, each component in the embodiment described above is a conceptual unit, and one component is composed of a plurality of structures within the scope of the technique disclosed in this specification. In addition, a case where one component corresponds to a part of a structure and a case where a plurality of components are provided in one structure are included.

  In addition, each component in the embodiment described above includes structures having other structures or shapes as long as the same function is exhibited.

  Also, the descriptions in the present specification are referred to for all purposes related to the present technology, and none of them is admitted to be prior art.

  DESCRIPTION OF SYMBOLS 11 Central apparatus, 12 millimeter wave base station apparatus, 13 Up line, 14 Down line, 15 Down train, 16 Up train, 17 Optical fiber, 18 Overlap area, 20, 20A Mixed base station apparatus, 21 UHF wave communication area, 22 mm Wave communication area, 30 on-board wireless device, 31 millimeter wave antenna, 32 UHF wave antenna, 33 millimeter wave radio, 34 UHF wave radio, 35 millimeter wave RSSI signal, 36 UHF wave RSSI signal, 37 millimeter wave communication data, 38 UHF wave communication data, 39 signal switching machine, 40 radio switching device, 41 signal discrimination circuit, 42 switching signal, 43 communication data.

Claims (5)

A plurality of base station devices arranged along the track;
A central device capable of communicating with each of the base station devices;
An on-board radio device mounted on a train traveling on the track and capable of communicating with a plurality of the base station devices;
The on-vehicle wireless device is capable of communication using a first radio wave that is a millimeter wave between at least one of the plurality of base station devices.
The on-board wireless device is capable of communication using a second radio wave having a longer wavelength than the first radio wave between at least one of the plurality of base station devices. ,
The on-board radio device performs communication using the first radio wave with each of the base station devices, and the reception intensity of the first radio wave received from the base station device is predetermined. When the communication is smaller than the threshold, the communication with the base station device is switched to the communication using the second radio wave.
Train communication system. The plurality of base station devices are:
Including a mixed base station apparatus capable of transmitting and receiving both the first radio wave and the second radio wave;
The train communication system according to claim 1. The plurality of base station devices are:
Including a millimeter wave base station device capable of transmitting and receiving the first radio wave,
The train communication system according to claim 2. When the millimeter wave base station device becomes unable to communicate, or when communication using the first radio wave with the mixed base station device becomes impossible, the on-board wireless device Switching communication with the station device to communication using the second radio wave,
The train communication system according to claim 3. The on-vehicle wireless device transmits and receives communication data including a driving command when performing communication using the second radio wave with each of the base station devices.
The train communication system according to any one of claims 1 to 4.

Images