JP4586890B2 - Traffic control system, transmission system conversion device, and UD type terminal device - Google Patents

Description

The present invention relates to a traffic control system, a transmission system conversion device , and a UD type terminal device .

The traffic control system comprises a central device of a traffic control center and various terminal devices installed on the roadside, and the central device communicates with the terminal device via a communication line. It is.
In the traffic control system, terminal devices installed on the roadside include optical beacons (also functioning as vehicle detectors) that perform two-way communication with in-vehicle devices, traffic flow data measurement terminal devices, vehicle detectors, There are traffic signal controllers that control traffic signals and traffic information boards that provide traffic information.

In addition, one traffic control center is generally installed for each city. In this traffic control center, traffic sensors, traffic conditions, time required, etc. are measured from various sensors (vehicle detectors, etc.) installed on the roadside. Collect information and perform analysis on a computer.
The central equipment installed in the traffic control center determines the optimal signal control parameters from the analyzed results, performs systematic control on the traffic signal controllers at each intersection, and traffic information using the traffic information board To provide.
Such a traffic control system is described in, for example, Patent Document 1 below.

Here, a communication system for transmitting data between the central device and each terminal is defined by the New Traffic Management System Association, and at present, serial communication using a so-called U-shaped transmission system using a LAPB procedure. Is often adopted.
As shown in FIG. 24, in the U-shaped transmission system, a dedicated line drawn from the central apparatus 100 for each terminal apparatus 101 as a communication line 102 connecting the U-shaped central apparatus 100 and the U-shaped terminal apparatus 101. It is necessary to provide. That is, many lines corresponding to the number of terminal apparatuses 101 are required for one central apparatus 100.

On the other hand, in recent years, a new transmission method incorporating IP technology, called a so-called UD type transmission method, has been established. In this UD type transmission method, routing can be performed to distribute data at the third layer (network layer) in the protocol stack. became.
JP 2001-23080 A

The UD type transmission system has the advantage of being able to construct a system at low cost because it can be controlled more advanced than the conventional U type transmission system and a network can be constructed using commercially available equipment using IP technology. is there.
Therefore, in consideration of future system development, it is desired to change the U-type transmission type apparatus to a new transmission type UD transmission type apparatus.
However, since there are a large number of existing U-type transmission terminal devices, it is expensive to update all of these existing terminal devices, which hinders changes to the new transmission method.

For this reason, the actual situation is that a new transmission system device and an existing U-shaped terminal device coexist. In this case, as shown in FIG. 25, the existing U-type transmission terminal device 101 as well as the new UD transmission type terminal device 111 exist as terminal devices managed by the system.
When both types of terminal devices 101 and 111 are mixed as terminal devices under system management, the U-type transmission method and the UD-type transmission method are defined by completely different standards. Therefore, in a system that cannot share the central device and adopts the UD type transmission method, not only the UD type central device 110 but also the U type central device 100 is required to control the U type terminal device 101.
As a result, the traffic control system needs to be divided into two systems: a system in which the U-shaped terminal device 101 is controlled by the U-shaped central device 100 and a system in which the UD-shaped terminal device 111 is controlled by the UD-shaped central device 110. The two central devices 100 and 110 are necessary, and the system development cost and the operation / maintenance cost increase.

As described above, at present, it is costly to change all devices to ones that support the new transmission method, and it is expensive to change some devices to ones that support the new transmission method. Therefore, it is difficult to shift to a new transmission method while suppressing costs.
Therefore, an object of the present invention is to allow a mixture of devices of different transmission methods in a traffic control system.

The present invention is a traffic control system comprising a central device for a traffic control system and a terminal device installed on the roadside, wherein the traffic control system is a UD transmission system and a terminal device. The central device that communicates with the central device is a transmission method having a different application data structure from the UD type transmission method, and the transmission method for the traffic control system does not employ IP in the third layer of the OSI reference model. The traffic control system further includes a transmission system conversion device that converts a transmission method interposed between the central device and the terminal device, and the transmission method conversion device includes: A first receiving unit that receives a UD type transmission method message from the central device, and a UD type transmission type message received by the first receiving unit is a third of the OSI reference model. A first conversion unit that converts the message into a transmission method for the traffic control system that does not employ IP in the layer, and the traffic control system that does not employ IP in the third layer of the OSI reference model converted by the first conversion unit A first transmission unit that transmits a message for a transmission system for a communication to the terminal device; a second reception unit that receives a message for a transmission method for a traffic control system that does not employ IP in the third layer of the OSI reference model; A second conversion unit for converting the traffic control system transmission method message that does not employ IP in the third layer of the OSI reference model received by the second reception unit into a UD transmission method message; e Bei a second transmission unit for transmitting a message of UD shaped transmission scheme that has been converted by the second converter unit to the central unit, wherein the first converter and the second Section is a traffic control system, characterized in that also performs conversion of the application data contained in the message.

According to the present invention , a message corresponding to the UD type transmission system is converted to a traffic control system transmission system message that does not employ IP in the third layer of the OSI reference model via a conversion device. Therefore, when viewed from the central device that performs communication using the UD type transmission method, even if the communication is performed with the terminal device that performs communication using the traffic control system transmission method that does not employ IP in the third layer of the OSI reference model, Communication similar to the case of these devices is possible.
Therefore, even if a central device and a terminal device corresponding to different transmission methods are mixed in the traffic control system, communication between them can be performed.
Similarly, messages from the terminal device to the central device can be received, converted, and transmitted.

Another aspect of the present invention is a traffic control system comprising a central device for a traffic control system and a plurality of terminal devices installed on the roadside, wherein the traffic control system is a UD type transmission system. The central device that communicates with the terminal device and the UD transmission method are transmission methods that have different application data structures, and the transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model. A plurality of terminal devices that perform communication, and the traffic control system further includes a transmission method conversion device that converts a transmission method by interposing between the central device and the plurality of terminal devices, the transmission system conversion apparatus, to the plurality of terminal devices are respectively connected by separate communication lines, and, for the central unit, are connected by a single communication line, it is The transmission system conversion apparatus for communication with said plurality of terminal devices, a message of UD shaped transmission method comprising UD shaped address assigned to each of the terminal device, via the one communication line, the The first receiving unit received from the central device and the UD transmission method message received by the first receiving unit are converted into the traffic control system transmission method message that does not employ IP in the third layer of the OSI reference model. Between the first conversion unit and the terminal device that is the transmission destination among the plurality of communication lines connected to the plurality of terminal devices based on the UD type address included in the message of the UD type transmission method. select the communication line via the communication line that has been selected, the converted by the first conversion unit, Den for the traffic control system that does not employ IP as the third layer of the OSI reference model Method messages, a first transmission unit that transmits to a destination the terminal device, the message of the traffic control system for a transmission system that does not employ IP as the third layer of the OSI reference model, is connected to the terminal device A second receiving unit received from the terminal device via the communication line, and a message of the transmission method for the traffic control system that does not adopt IP in the third layer of the OSI reference model received by the second receiving unit, A second conversion unit that converts the message into a UD type transmission method; and a UD type address assigned for communication with a terminal device that has transmitted the message to the UD type transmission method message converted by the second conversion unit. addition to, through the one communication line, the second transmission section Preparations example the first conversion unit and the and the second transformation unit for transmitting to the central unit, including the message It is a traffic control system characterized by also converting application data .
The transmission system for the traffic control system that does not employ IP in the third layer of the OSI reference model is preferably an M-type transmission system.
The terminal device communicates with the central device by the UD type transmission method in addition to the terminal device that communicates with the central device by the transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model. UD type terminal devices are mixed, and the transmission method conversion device is configured such that the transmission destination of the message of the UD type transmission method received from the central device or the UD type terminal device is the UD type terminal device or the central device. In some cases, the received message of the UD type transmission scheme is transmitted to the UD type terminal device or the central unit which is the transmission destination without being converted by the first conversion unit or the second conversion unit. preferable.
Another aspect of the present invention is a transmission system that is installed on the roadside of a central device for a traffic control system that communicates with a terminal device using a UD transmission system, and has a different application data structure from the UD transmission system. In a traffic control system that includes a terminal device that communicates with a central device using a transmission method for a traffic control system that does not employ IP in the third layer of the OSI reference model, between the central device and the terminal device. A transmission system conversion apparatus for intervening conversion of a transmission system, the first receiving unit receiving a UD transmission system message from the central device, and the UD transmission system message received by the first receiving unit Is converted into a message of the transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model, and the first conversion unit The first transmission unit that transmits the message of the transmission method for the traffic control system that does not adopt IP to the third layer of the OSI reference model, converted to the above, and the IP to the third layer of the OSI reference model A second receiving unit that receives a message of the transmission method for the traffic control system from the terminal device, and a transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model received by the second receiving unit A second conversion unit that converts the message of UD type into a UD type transmission method message, and a second transmission unit that transmits the UD type transmission method message converted by the second conversion unit to the central device, In the traffic control system, the first conversion unit and the second conversion unit also perform conversion of application data included in a message. A transmission system conversion apparatus.
A terminal device that is a transmission destination of the message of the transmission method for the traffic control system converted by the first conversion unit from a plurality of communication lines connected to each of the plurality of terminal devices connected to the transmission method conversion device It is preferable to perform control for selecting a communication line connected to the network.
Another aspect of the present invention is a UD type terminal device for a traffic control system, comprising the transmission mode conversion device according to claim 5 or 6, wherein the UD type terminal device has a transmission mode conversion function. is there.
The UD transmission method and the transmission method that does not employ IP in the third layer of the OSI reference model are such that both the part related to the communication procedure of the message to be transmitted and the application data used by the application are between the two transmission methods. It is different, and it is preferable that the conversion means has a function of converting a part related to the communication procedure and the application data between both transmission methods. In this case, the conversion means can convert these differences even if both the transmission protocol part and the application data are different between the two transmission systems, such as the U-type transmission system and the UD-type transmission system. Communication between the central device and the terminal device becomes possible.

The second receiving unit is preferably controlled to receive messages from a plurality of terminal devices. In this case, the second receiving unit, for enabling the message received from a plurality of terminal devices, it is possible to connect a plurality of terminal devices to the transmission system conversion apparatus of the present invention, the connection structure of the network can be simplified it can.

It is preferable that the first transmission unit is controlled so as to perform message transmission to a plurality of terminal devices. In this case, the first transmission unit, for enabling the message transmissions to a plurality of terminal devices, it is possible to connect a plurality of terminal devices to the transmission system conversion apparatus of the present invention, the connection structure of the network can be simplified it can.

The first and second conversion units convert information related to communication procedures between a routable UD transmission system and a transmission system that does not employ IP ( non-routable ) in the third layer of the OSI reference model. It is preferable to enable routing even in communication between a device compatible with a routable communication method and a device compatible with a non-routable transmission method. In this case, even if the traffic control system includes a device corresponding to a non-routable transmission method such as a U-shaped transmission method, a message of a non-routable transmission method is routed by the routing technology of the conversion device and the message is selected. Therefore, a system with a high degree of freedom / development can be constructed in the same manner as a system configured only by devices compatible with the routable UD type transmission system.

A conversion table storing correspondences between message types and message IDs in the UD type transmission system, and terminal types and information types in the U type transmission system;
The first conversion unit and the second conversion unit preferably convert a message by referring to the conversion table.
In the case of a traffic control system, even if the data portion used by an application differs depending on the transmission method, the control content in the traffic control system is common, so the correspondence between them is relatively high. By utilizing this, by preparing a table indicating the correspondence between between the transmission method, it can be easily converted.

When a UD transmission method message is received from the central device, a reception response to the message is preferably transmitted to the central device without waiting for a reception response from the terminal device. Since there are cases where the reception response is sent differently between different transmission methods, waiting for a reception response from the transmission destination does not always return the reception response reliably. Therefore, as described above, the reception response, by transmitting directly to the central unit that originated the message from the conversion device of the present invention, the central unit can be obtained reliably receive the response.
Even when a message is received from the terminal device, the conversion device can similarly send a reception response.

When the first receiving unit receives a non-corresponding message for which there is no corresponding message in the U-type transmission method among messages in the UD-type transmission method, the first conversion unit converts the message and the first transmission unit performs U It is preferable not to transmit the message of the form transmission system.
In addition, when the second receiving unit receives a non-corresponding message for which there is no corresponding message in the UD transmission method among messages in the U transmission method, the second conversion unit converts the message, and the second It is preferable that the transmission unit does not transmit a message of the UD type transmission method.
There are cases where messages do not completely correspond one-to-one between different transmission schemes, and there is no U-type transmission scheme application data corresponding to UD transmission scheme application data. Such a case can be dealt with by not transmitting the received message to the terminal device.
The transmission in the case of receiving a message U-shaped transmission system, even when the application data UD shaped transmission method corresponding to the application data U-shaped transmission system does not exist, similarly the message to the message conversion and the central unit It can respond by not doing.
Further, when the message is not transmitted to the transmission destination, the conversion apparatus may appropriately generate a message for the transmission source and transmit the message to the transmission source.

When the received message is a message to be transmitted to a device corresponding to the same transmission method, it is preferable to transmit the message to the communication partner device without performing message conversion. In this case, not only communication between devices with different transmission methods but also communication between devices corresponding to the same transmission method can be performed via the conversion device, so the central device or terminal device is a device with the same transmission method as the communication partner. Even if there are different transmission systems, communication is possible without distinguishing between them, and the degree of freedom of communication is increased.

  From another point of view, the present invention provides a traffic control system in which a first device that communicates with a first transmission method and a second device that communicates with a second transmission method are mixed as devices constituting a traffic control system. In order to convert between the first transmission method and the second transmission method, a computer receives a message of the first transmission method from the first device, and receives the received message of the first transmission method in the second A computer program for executing a step of converting to a message of a transmission method and a step of transmitting a message of the second transmission method obtained by the conversion to the second device.

From another viewpoint, the present invention is a traffic control system including a central device and a plurality of terminal devices that perform data communication with the central device, and the central device supports a routable transmission method. The plurality of terminal devices include those corresponding to other non-routable transmission methods, and a message of one transmission format is sent between the central device and the plurality of terminal devices to the other. The traffic control system is provided with a conversion device for converting the message into a transmission system message, and communication between the central device and the plurality of terminal devices is performed via the conversion device.
According to this traffic control system, a terminal device corresponding to a non-routable transmission method can be included in a traffic control system having a central device corresponding to a routable transmission method such as the UD transmission method. From the viewpoint of a device, a device corresponding to a transmission method that cannot be routed can be controlled in the same manner as a device corresponding to a transmission method capable of footing.

  It is preferable that a plurality of terminal devices corresponding to the other transmission methods that cannot be routed are connected to the conversion device, and each communication between the central device and the plurality of terminal devices can be controlled. In order to connect a terminal device and a central device corresponding to another transmission method that cannot be routed, a number of communication lines corresponding to the number of terminal devices is required. Even when a plurality of terminal devices compatible with other transmission methods are connected, the routing technology can perform communication between a plurality of terminals and the central device with a small number of lines even if there is no communication line corresponding to the number of terminal devices.

The transmission system conversion device may be configured as a device separate from other devices constituting the traffic control system, or for a traffic control system such as a traffic signal controller capable of data communication with a central device. The terminal device may be configured as a terminal device having a transmission method conversion device (transmission method conversion function) by incorporating the function of the transmission method conversion device.
By providing the terminal apparatus (for example, traffic signal controller) with the transmission system conversion function, it is not necessary to install the transmission system conversion apparatus separately from the terminal apparatus, and the installation work burden of the apparatus can be reduced.
In a traffic control system including a central device and a plurality of terminal devices that perform data communication with the central device, the plurality of terminal devices include a terminal device with a transmission method conversion function. It is preferable that communication between another terminal device and the central device is performed via a terminal device with a conversion function.

The transmission system conversion device may be installed on the road or may be installed in a traffic control center.
In a traffic control system that performs data communication between a central device installed in a traffic control center and a terminal device installed on the road, a transmission method conversion device installed on the road or in the traffic control center is used. It is preferable to perform communication between the central device and the terminal device.

  According to the present invention, since messages are converted between different transmission methods, communication is possible even if devices of different transmission methods are mixed in the traffic control system.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a traffic control system, which includes a central device 1 installed in a traffic control center, a transmission system converter 2 connected to the central device 1 via a communication line 5, Various terminal devices 3-1, 3-2, 3-3, 3-4 such as traffic signal controllers and vehicle detectors installed at intersections (hereinafter referred to as “terminals” when each terminal device is called without distinction) Device 3 ”), and the traffic control system is operated by performing communication between the central device 1 and the terminal device 3.

The central device 1 of this traffic control system is a device capable of controlling a so-called UD type transmission system (UD type central device), and the terminal device 3 is a device corresponding to the so-called U type transmission method (U type terminal device). .
In this system configuration, for example, when there is a traffic control system configured by connecting a U-shaped terminal device 3 to a U-shaped central device that controls a U-shaped transmission system, the U-shaped central device is converted into a UD-shaped device. In this case, the central device 1 is replaced and the existing UD terminal device 3 is controlled and operated by the UD central device 1.
The transmission method conversion device 2 in this system enables communication between the devices 1 and 3 by converting messages between the devices 1 and 3 that perform communication by different transmission methods.

The conversion device 2 is installed at any position on the communication paths 5 and 6 between the central device 1 installed at the traffic control center and the terminal device 3 such as a traffic signal controller installed at an intersection or the like. However, the conversion device 2 is preferably installed in the vicinity (on the road) of the terminal device 3.
Communication is performed between the central device 1 and the conversion device 2 through a dedicated line 5 such as “analog dedicated line of band item 3.4 kHz”, and if there is one communication line connected to the central device 1. It ’s enough.
Further, the conversion device 2 can draw a plurality of communication lines for the terminal device 3, and the conversion device 2 can be connected to the plurality of terminal devices 3. A dedicated line is preferable between the conversion device 2 and the terminal device 3, but in the case of a short distance, communication may be performed via a private line 6 that extends for each terminal device 3.

As described above, since a plurality of U-shaped terminal devices 3 are connected to the terminal device 2 and aggregated in the conversion device 2, the number of communication lines connected to the central device 1 is smaller than the number of terminals. (1) is enough.
Further, since the conversion device 2 is installed in the vicinity of the terminal device 3 and the distance between the conversion device 2 and the terminal device 3 is relatively short, even if there are a plurality of communication lines, the cost does not increase so much. On the other hand, since the central device 1-terminal device 3 having a relatively long distance can be operated with a small number of lines, the line maintenance / operation costs can be reduced.

FIG. 2 shows a comparison of protocol layers (other than the physical layer) in the OSI reference model of the U-type transmission system and the UD-type transmission system. In the U-shaped transmission system, the functions of the network layer, transport layer, session layer, presentation layer, and application layer of the OSI reference model are collectively defined as an application (devices 1 and 3).
On the other hand, in the UD type transmission system, the functions of the session layer, presentation layer, and application layer of the OSI reference model are collectively defined as an application (devices 1 and 3), as in a general UDP / IP system.
Comparing both transmission methods, the protocol is different from the lower layer, and in order to convert the message, first convert the data link layer, interpret the header information above the network layer, and change the header information adapted to it. Need to be generated.

Here, communication standards for traffic control systems such as the so-called U-type transmission system and UD-type transmission system are defined by the New Traffic Management System Association.
FIG. 3 shows a group of standards constituting the U-shaped transmission system. The U-shaped transmission system referred to here is a “U-shaped interface standard” as a standard for the physical layer and the data link layer, and a standard for an upper layer. It consists of “end application standards for each device used in the U-shaped transmission system” (message standards) such as “U-shaped communication application common standard” and “U-shaped traffic signal controller U-shaped communication application standard”. Note that the “end application standard for each device used in the U-shaped transmission system” is not the name of the standard, and there are a number of standards corresponding to the types of terminal devices. For the sake of convenience.

FIG. 4 shows a group of standards constituting the UD type transmission system. The UD type transmission system referred to here is “UD type interface standard” and “S9 type interface” as physical layer and data link layer standards. "Standard", "UD type transport standard" as network layer and transport layer standard, "DATEX-ASN communication application standard", "UD type encoding standard", "U / UC type traffic" as higher layer standard It consists of “end application standards for each device used in the UD type transmission system” (message standards) such as “signal controller DATEX-ASN message standard”. Incidentally, the end application standard for each device used in U D-type transmission system ", rather than the name of the standard, the standard corresponding thereto are provided a number depending on the type of terminals, a number of these standards For the sake of convenience.

In the U-type transmission method, a protocol of the LAPB procedure + U-type interface standard is used as a communication protocol (communication procedure), and the basic configuration of the message (message) frame (transmission frame) is as shown in FIG. . The illustrated frame includes an HDLC header and a trailer as a part relating to a communication procedure, and includes data (application data; information part (I)) used by an application in the U-shaped transmission system between the HDLC header and the trailer.
Note that the illustrated frame is an information frame having the information part (I), but there is a monitoring frame that does not have the information part (I) to be transmitted.

  The message (information frame) shown in FIG. 5 includes, as an HDLC header, a flag sequence (F) for recognizing the start of the frame, an address (A) indicating a transmission destination, and a control unit (C) for transmission control. ing. The trailer also includes a frame check sequence (FCS) for error control and a flag sequence (F) for recognizing the end of the frame.

Application data (information section (I)) is used by an application (central device or terminal device) in the U-shaped transmission system shown in FIG. 2 for operation and control, and includes a header (I-H). And the application data body (IB).
Application data body (IB) is actually used by U-shaped central unit and U-shaped terminal device to control the content of data for controlling traffic signals and the content of data detected by vehicle detectors Data to be included.
The header (IH) of application data (information part (I)) is configured as shown in FIG. The header (I-H) includes a destination address and a source address (see transmission order 2 and 3 in FIG. 6), and further includes a terminal type and an information type (transmission order in FIG. 6). 7 and 8).

The destination address indicates an address assigned to a destination device (U-shaped central device or U-shaped terminal device), and the source address is a source device (U-shaped central device or U-shaped terminal). This indicates an address assigned to the (device).
The terminal type is information indicating the type of the terminal device, and the information type is information indicating the information type of the application data body. These terminal information and information type are used as information relating to the type of the application data body (IB).
The header also includes the data length (see transmission order 10 in FIG. 6), and this data length indicates the data length of the application information section (IA).

  In the UD type transmission system, PPP and UDP / IP are used as communication protocols (communication procedures), and the basic structure of the frame of the message (message) is as shown in FIG. In the illustrated frame (PPP frame), an IP header (IP frame) is added to a user data which is a message of DATEX-ASN transmission with a UDP header (UDP frame), and a PPP header (F, A , C, protocol) and trailer.

In the message of the UD type transmission system, the part excluding user data (application data) is a part related to the communication procedure. Specifically, the PPP header (F, A, C, protocol) and the trailer (the above is the PPP). ), IP header (portion related to IP), and UDP header (portion related to UDP) are portions related to the communication procedure.
The image of data transmission in UDP / IP here is (DATEX-ASN transmission on UDP / IP), that is, the data (application data) in DATEX-ASN transmission is encapsulated and packetized in UDP / IP. To be transmitted.

User data which is a telegram of DATE-ASN transmission of the UD type transmission system corresponds to application data used by the application in the UD type transmission system shown in FIG. 2 for operation and control.
The DATEX-ASN transmission data has a data structure shown in FIG. 8, and in this data structure, version information, a data part, and a CRC data item are provided. The data part further includes authentication information, a data packet number, a priority. Data items such as option information and PDU. Here, the PDU is a message exchanged between end applications, and ASN. 1 has the structure shown in FIG. In the structure of FIG. Message Body (message body) which is a message body by 1 notation, Message Type (message type) indicating whether the message is an information request message or an information distribution message, Id which is an object identifier of the message, and the like are included.

Here, the Message Body (message body) in FIG. 9 is actually used in the UD type central or UD type terminal device for controlling the content of the data for controlling the traffic signal and the content of the data detected by the vehicle sensor. Contains data used for.
Further, the message type and the Id are used as information related to the type of Message Body (message body) which is a message body.
As described above, although the UD-type transmission message has a different data structure, the application data includes information related to the message body and the type of the message body, similarly to the U-type transmission message.

As described above, the communication protocol (communication procedure) in the U-type transmission system is in the data link layer (LAP-B), and the communication protocol in the UD-type transmission system is in the data link layer, the network layer, and the transport layer. (PPP, UDP / IP), and the communication protocol standards of the two are also different. Therefore, the U-type and the UD-type are completely different in the part related to the communication procedure of the transmitted message.
Also, among the constituent parts of the message to be delivered, the application data part used by the application has different standards for both transmission methods, so that the application data in the U-type transmission method (see FIG. 5) and the UD-type transmission method The application data (see FIG. 7) also has a completely different data structure (see FIGS. 6, 8, and 9).
However, in the application data, what is completely different between the two transmission methods is a part other than the application data body, and the application data body (FIGS. 5 and 9) actually used for control in the application is slightly different. In some cases, they are almost the same and have high commonality.

Furthermore, in the UD type transmission system, communication route selection (routing) can be performed in the third network layer in the OSI reference model. In the UD type transmission system, routing can be performed with a protocol at a lower layer than the application, so that future development and expandability of the traffic control system can be expected without depending on the application. Further, in the UD type transmission system, since routing is possible, the number of communication lines between the central device and the terminal device is not required corresponding to the number of terminals.
On the other hand, in the U-type transmission system, the lower layer than the application is the data link layer, and routing cannot be performed in the data link layer. Therefore, it is necessary to draw one communication line from the U-shaped central device for each U-shaped terminal device having a communication function, and a large number of communication lines are required between the U-shaped central device and a plurality of terminal devices. Is.

Returning to FIG. 1, in this traffic control system, the central device 1 is compatible with the U-type transmission method, whereas the terminal device 3 is compatible with the UD-type transmission method, and the devices 1 and 3 of both transmission methods are mixed. ing. Therefore, the message of the terminal device 3 transmitted from the central device 1 is a UD type transmission method message, and the message that can be received by the central device 1 is also a UD type transmission method message.
Further, the message of the central device 1 transmitted from the terminal device 3 is a U-type transmission method message, and the message that can be received by the terminal device 3 is also a U-type transmission method message.

The transmission method conversion device 2 converts both types of messages having different communication procedures and application data to each other to convert between the UD type device (U type central device) 1 and the U type device (U type terminal device) 3. Message exchange is possible. As shown in FIG. 10, the transmission method conversion apparatus 2 includes a central line unit 21 for communicating with the central apparatus 1 and a terminal line unit 22 for communicating with a plurality of terminal apparatuses 3.
The conversion device 2 further includes a communication control unit 23 that performs control related to conversion of messages distributed between the central device 1 and the terminal device 3 and other communication.

FIG. 11 shows a block diagram related to a message conversion function (conversion means) among the functions in the conversion device 2. As shown in the figure, the conversion apparatus 2 includes a receiving unit 201 and a transmitting unit 202 that transmit and receive a U-type transmission system message, and a transmitting unit 203 and a receiving unit 204 that transmit and receive a UD-type transmission system message. The U-type transmission system message (transmission message from the terminal device 3 to the central apparatus 1) received by the U-type message reception unit 201 is converted into a UD-type transmission system message by the U-UD message conversion unit 205. The message is transmitted by the message transmitter 203 (to the central apparatus 1). Also, a UD transmission method message (a transmission message from the central device 1 to the terminal device 3) received by the UD message reception unit 204 is converted into a U transmission message by the UD-U message conversion unit 206. It is transmitted (to the terminal device 3) by the U-shaped message transmission unit 202.
Message conversion by the conversion unit (conversion means) is performed by referring to the conversion library 207 (details will be described later).

As shown in FIG. 12, when the conversion apparatus 2 receives a U-shaped transmission message from the U-shaped terminal apparatus 3 using the protocol of the LAPB procedure + U-shaped interface standard (step S11), the U-shaped message receiving unit 201 transmits a U-shaped message. The reception notification is made to the unit 202, and the transmission unit 202 transmits a reception response to the terminal device 3 that has transmitted the message (step S12).
The U-UD message conversion unit 205 includes a U-shaped transmission message analysis unit 205a (see FIG. 11), and the analysis unit 205 analyzes the received U-shaped transmission message (steps S13 and S14). Specifically, the analysis unit 205a identifies the HDLC header (see FIG. 5) of the U-shaped transmission message (step S13). Further, the analysis unit 205a uses the destination address and the source address (see FIG. 6) included in the data item of the header (IH) (see FIG. 5) of the information part (I) of the U-shaped transmission message to determine the U The transmission destination / source of the shaped transmission message is identified (step S14a). Further, the information type / terminal type (see FIG. 6) included in the data item of the header (IH) is identified (step S14b), and the data length of the header (IH) (FIG. 6) is also identified. Read) (step S14c).

  Subsequently, the application data body (IB) (see FIG. 5) is extracted from the received U-shaped transmission message based on the data length read in step S14c (step S15). The U-type application data body extracted in step S15 is used as the Message Body (message body) in FIG. 9 which is a UD-type application data body. The application data body (IB) of the U-shaped transmission message and the Message Body of the UD-shaped transmission message are almost the same, and can be used as they are. Is done.

Also, the conversion unit 205 refers to the data body type information conversion table 207a (see FIGS. 11 and 13) of the conversion library 207 based on the information type and terminal type (data body type information) identified in step S14b. Then, the message type and Id (data body type information) of the UD type transmission message corresponding to the information type and terminal type of the received U type transmission message are created (step S16a: data body type information creation process).
Since the control contents of the application are relatively common between the U and UD transmission systems, “U type transmission system information type and terminal type” and “UD type transmission system” are information indicating the type of the application data body. Although the data structure itself is different, the message type and Id ”of FIG. 13 are almost compatible as shown in FIG. Therefore, the data body type information can be easily converted between the two transmission systems by using the table 207a (see FIG. 13) that defines this correspondence.

  Further, the conversion unit 205 automatically generates data items other than the Message Body, message type, and Id obtained by the above processing as shown in FIGS. The entire application data (DATEX-ASN transmission data) is completed (step S16).

Then, the conversion unit 205 refers to the address conversion table 207b (see FIGS. 11 and 14) of the conversion library 207 based on the destination / source information of the U-shaped message identified in step S14a (see step S14a). Then, a UD transmission system address corresponding to the U transmission system address is created (step S17a).
The address conversion table 207b defines addresses in each transmission method of each device (central device 1, terminal device 3) in the traffic control system. In the illustrated table 207b, the addresses enclosed by squares are the original addresses of the devices 1 and 3. For example, since the central device 1 is the UD type, the original address is the UD type address (address B1), and the table 207b defines the U type address (address A1) corresponding to the UD type address of the central device. Yes.
Therefore, if a message is transmitted from the U-shaped terminal device 3 using the U-shaped address on the assumption that the central device is U-shaped, the conversion device 2 converts the message into a UD-shaped address.

  Furthermore, the conversion unit 205 adds the created address and other information automatically generated as appropriate, and creates a UDP header, an IP header, and the like, which are parts related to the communication procedure of the UD transmission method (step S17). Then, a UD-type HDLC header (usually substantially the same as the U-type HDLC header) is created from the U-type HDLC header identified in step S13 (step S18).

  The UD-type data created as described above are combined as shown in FIG. That is, a UDP header is formed by adding a UDP header to DATEX-ASN transmission data, which is UD type application data, an IP header is formed by adding an IP header to the UDP frame, and a PPP header and trailer are added to the IP frame. Thus, a PPP frame is formed.

  The generated UD-type transmission message is transmitted from the UD-type transmission message transmission unit 203 to the UD-type central apparatus 1 using the PPP and UDP / IP protocols (step S19). In this way, the U-shaped transmission message can be transmitted from the U-shaped terminal device 3 to the central device 1 as if the central device 1 is a U-shaped central device by passing the message through the conversion device 2. The UD type central device 1 can receive a UD type transmission message from the terminal device as if the terminal device 3 is a UD type terminal device.

From the viewpoint of the U-shaped terminal device 3, each terminal device 3 communicates with the U-shaped transmission method using the communication line 6 connected to the terminal device 3. The communication line 5 is aggregated by the UD type transmission system at the front (central device 1 side).
That is, since the conversion device 2 can convert U-shaped application data into IP packets by UDP / IP, the collection and distribution of packets can be freely performed in the network layer, and the number of messages from a plurality of terminal devices 3 can be reduced. Since the number (one) can be transmitted to the central device 1, the number of lines between the central device 1 and the conversion device 2 can be aggregated.

As shown in FIG. 15, conversely to the above, when the conversion device 2 receives a UD transmission message from the UD central device 1 (step S21), the reception notification is sent from the UD message reception unit 204 to the UD message transmission unit 203. The transmission unit 203 transmits a reception response to the central device 1 that has transmitted the message (step S22).
Thereafter, analysis of the UD-type transmission message, UD-U conversion, and generation of the U-type transmission message are performed by processing reverse to the processing shown in FIG. 12 (steps S23 to S28). The generated U-shaped transmission message is transmitted from the U-shaped message transmission unit 202 to the terminal device 3 via the line 6 with the terminal device 3 having the designated address.

Also in this case, since the message passes through the conversion device 2, the UD type central device 1 transmits the UD type transmission message to each terminal 3 as if each terminal device 3 is a UD terminal device. it can.
That is, the conversion device 2 functions as a router (IP router) with respect to the U-shaped terminal device 3 using the IP address included in the UD-shaped transmission message, and connects the plurality of U-shaped communication paths 6 connected to each other. U-type terminal device that cannot perform routing when viewed from the central device 1 in order to perform control for selecting the U-shaped communication path 6 with the terminal device 3 that is the transmission destination designated from the conversion device 2 3, communication by routing similar to that of the UD terminal device can be realized.

FIG. 16 shows an example of communication between the central device 1 and the terminal device 3, and in the case of “(1) normal”, a message requesting information is transmitted from the central device 1 to the terminal device 3, This is a case where the terminal device 3 transmits (distributes) a message carrying the requested information to the central device 1. In this case, when an information request UD transmission message is transmitted from the central device 1 to the terminal device 3 (1-1), the conversion device 2 converts it into a U-shaped transmission message and transmits it to the terminal device 3. (1-2). The terminal device 3 uses the requested information as the application data body (information section (I)) and sends a U-shaped transmission message for information distribution to the central device 1 (1-3). It is converted into a transmission message and transmitted to the central device 1 (1-3).
The case of “(1) normal” in FIG. 16 shows a case where both the information request message and the information delivery message correspond to both transmission methods, and the processing shown in FIGS. It is what.

On the other hand, as shown in the table 207a in FIG. 13, there is a case where there is no message (data body type) corresponding to both transmission methods. For example, among the information request message and the information distribution message in the UD type transmission system, some messages do not have a corresponding message in the U type transmission system. Here, a message for which there is no corresponding message in another transmission method is referred to as a “non-corresponding message”.
An example of such communication is shown in “(2) UD type only” in FIG. 16, and when an information request message, which is a UD type non-corresponding message, is transmitted from the central device 1 to a specific terminal device ( 2-1) The conversion device 2 does not perform conversion to the U shape or transmission to the terminal device 3.
That is, as shown in FIG. 17A, when the table 207a is referred to obtain the U-shaped data body type information corresponding to the data body type information in the UD message (step S31), the corresponding U-shaped If there is no data main body type information, generation of the U-shaped terminal type / information type and other conversion processing (processing of FIG. 15) are not performed, and transmission processing to the terminal device 3 (step S29) is not performed.
Instead, the conversion device 2 generates the requested information by itself, creates a UD transmission message (information distribution message) for distribution to the central device 1, and transmits it to the central device 1 (2-2). ). Therefore, even in such a case, the central apparatus 1 can obtain the requested information.

  Similarly, the case of a message that exists only in the U-type transmission system is shown in “(3) U-type only” in FIG. 16, and in this case, as shown in FIG. 12 (3-1), the conversion device 2 itself transmits the U-shaped transmission to the U-shaped terminal device 3 without performing the processing shown in FIG. 12 such as the creation of the UD-shaped message type / Id (step S16a). A message (delivery message) is created and returned to the terminal device 3 (3-2). Therefore, even in such a case, the terminal device 3 can obtain the requested information.

FIG. 18 shows a modification of the traffic control system. The traffic control system shown in the figure is the UD type for the central device 1 as in the traffic control system described above, but among the plurality of terminal devices, the UD type terminal devices 30-1 and 30-2, U-shaped terminal devices 3-1 and 3-2 are mixed.
In this system configuration, for example, when there is a traffic control system configured by connecting a U-shaped terminal device 3 to a U-shaped central device that controls a U-shaped transmission system, the U-shaped central device is converted into a UD-shaped device. The central device 1 is replaced, and a part of the existing U-type terminal device 3 is replaced with a UD-type terminal device. The central device 1 allows both the existing U-type terminal device 3 and the new UD-type terminal device 30 to be replaced. This is a case where the operation is controlled.

The conversion device 2 used in this system includes a central line unit 21 and a communication control unit 23 as shown in FIG. 10, but the terminal line unit includes both terminal devices 3 and 30 ( Here, a UD-type terminal line unit 22a and a U-type terminal line unit 22b are provided so that they can be connected.
The conversion device 2 enables communication between the UD type central device 1 and the U type terminal device 3 as indicated by an arrow in FIG. 18, and between the UD type central device 1 and the UD type terminal device 30. Communication is also possible.

  The communication between the UD type central device 1 and the U type terminal device 3 is performed as described above, and the communication between the UD type central device 1 and the UD type terminal device 30 is performed by the conversion device 2 with a message. This is done by sending the data as it is without conversion. That is, as shown in FIG. 20, when the conversion device 2 receives a UD type transmission message from the UD type device (central device 1 or terminal device 30) (step S41), the transmission destination is the UD type device from the content of the message. It is determined whether or not there is a U-type device, that is, a message (UD-UD message) from the UD-type device to the UD-type device (step S41). If the message is to the U-shaped device, the UD-U message conversion process (step S43) is performed as described above, and the generated U-shaped transmission message is transmitted (step S44). If there is no need for conversion, the data is transmitted to the UD type device without conversion (step S45).

  As described above, in the conversion device 2, the communication path can be appropriately selected by UDP / IP. Therefore, the U-type terminal device 3 and the UD-type terminal device 30 can be integrated to communicate with the central device 1. In addition, the conversion device 2 can cope with communication between the UD type terminal devices 30 and 30 in the same manner as the communication between the UD type central device 1 and the UD type terminal device 30 is possible. For example, when there is a vehicle detector and a traffic signal controller as a UD terminal device by this UD type inter-terminal communication, control that does not pass through the central device 1 by directly transmitting the detection signal of the vehicle detector to the traffic signal device. And the load on the central device 1 can be reduced.

FIG. 21 shows still another modification of the traffic control system. In the illustrated traffic control system, the central device 1 is a UD type as in the traffic control system described above, but only the U-type terminal device 3 and the UD-type terminal device 30 are included in a plurality of terminal devices. In addition, an M-type terminal device 35 that performs communication by a so-called M-type transmission method is also included. Note that the M-type transmission method is a non-routable transmission method similar to the U-type transmission method.
The conversion device 2 used in this system is also provided with a central line unit 21 and a communication control unit 23 as shown in FIG. 10, and the terminal line unit includes terminal devices 3, 30, 35 of each method. A U-type terminal line unit, a UD-type terminal line unit, and an M-type terminal line unit are provided so that a plurality of terminals may be connected.
The converter 2 has the function of the converter 2 shown in FIGS. Further, the conversion device 2 has a function of performing not only UD-U conversion and U-UD conversion of messages but also UD-M conversion and M-UD of messages. Communication (message exchange) with the terminal device 35 is possible.
Also in this conversion device 2, communication paths can be appropriately selected by UDP / IP, so that the U-type terminal device 3, the UD-type terminal device 30, and the M-type terminal device 35 are aggregated to communicate with the central device 1. Can do.

FIG. 22 shows still another modification of the traffic control system. In this traffic control system, a UD type terminal device 30-1 with a transmission method conversion function having the same function as the transmission method conversion device 2 described above is provided instead of the transmission method conversion device 2 in the traffic control system of FIG. It has been. The UD type terminal device 30-1 is configured, for example, as a traffic signal controller, and the UD type terminal device 30-1 is provided with a processing device that realizes a transmission system conversion function. The other terminal devices 3, 30-2 and 35 constituting the traffic control system can communicate with the UD central device 1 via the UD terminal device 30-1 with a transmission method conversion function. .
According to the system configuration of FIG. 22, it is not necessary to install the transmission method conversion device 2 on the road (near the road) separately from the terminal device, so that space saving and installation work can be omitted.
Note that the terminal device 30-1 with a transmission method conversion function need not be a UD type terminal device, and may be a terminal device of another type such as a U type terminal device. Further, a plurality of terminal devices with a transmission method conversion function may exist in the traffic control system.

  FIG. 23 shows still another modification of the traffic control system. In this traffic control system, the transmission method conversion device 2 in the traffic control system of FIG. 21 is installed on the road (near the road), whereas the transmission method conversion device 40 is installed in the traffic control center. In the traffic control system of FIG. 21, since the central device 1 and the transmission method conversion device 2 are at a long distance, communication is performed using the dedicated line 5. However, in the system of FIG. Since the transmission method conversion device 40 is a short distance, communication is performed via the LAN, and the transmission method conversion device 40 and the terminal devices 3, 30, and 35 on the road (near the road) communicate via the dedicated line 5, respectively. Configured to do. When the dedicated line 5 between each terminal device 3, 30, 35 and the traffic control center can be secured sufficiently, as shown in FIG. 23, the transmission system conversion device 40 is installed in the traffic control center. It is preferable because maintenance inspection of the system conversion device 40 is facilitated.

  The present invention is not limited to the above embodiment. In particular, the transmission method to be converted in the present invention is not limited to the U-type, UD-type, and M-type, and other existing transmission methods and transmission methods newly established in the future are also targeted. Can do.

It is a network block diagram of a traffic control system. It is a protocol layer in the OSI reference model of the U type transmission system and the UD type transmission system. It is a conceptual diagram which shows the standard group of a U-shaped transmission system. It is a conceptual diagram which shows the standard group of a UD type transmission system. It is a frame block diagram of the message of a U-shaped transmission system. It is a data block diagram of the header (IH) of FIG. It is a frame structure figure of the message of a UD type transmission system. It is a data block diagram of DATEX-ASN transmission. 9 is a message definition in the PDU of FIG. It is a block diagram of a transmission system converter. It is a functional block diagram regarding the message conversion function in a transmission system converter. It is a figure which shows the process of U-UD conversion. It is a data main body type information conversion table. It is an address conversion table. It is a figure which shows the process of UD-U conversion. It is a figure which shows the information request | requirement / delivery procedure between a central apparatus and a terminal device, (1) is normal, (2) is the data which exists only in UD form, (3) is only U form This is the case of data existing in It is a flowchart which shows a process when the data main body classification information (application data) corresponding between both transmission systems does not exist, (a) shows the case of UD-U conversion, (b) shows the case of U-UD conversion. ing. It is a network block diagram which shows the modification of a traffic control system. It is a block diagram of the transmission system converter of FIG. FIG. 18 is a flowchart illustrating processing when a UD type transmission message is received in the transmission method conversion apparatus of FIG. 17. FIG. It is a network block diagram which shows the other modification of a traffic control system. It is a network block diagram which shows the other modification of a traffic control system. It is a network block diagram which shows the other modification of a traffic control system. It is a network block diagram in a U-shaped transmission system. It is a network block diagram at the time of mixing U type transmission system and UD type transmission system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 UD type | mold central apparatus 2 Transmission system converter 3 U type | mold terminal device 201 U type | mold message receiving part (reception means)
202 U-shaped message transmission unit (transmission means)
203 UD type message transmitter (transmission means)
204 UD type message receiver (reception means)
205 U-UD message converter (converter)

Claims (7)

A traffic control system comprising a central device for a traffic control system and a terminal device installed on the roadside,
The traffic control system is a transmission method having a different application data structure from the central device that communicates with the terminal device in the UD type transmission method, and adopts IP in the third layer of the OSI reference model. It is a configuration that includes a terminal device that communicates with the central device in a transmission method for a traffic control system that does not
Further, the traffic control system includes a transmission method conversion device that converts a transmission method interposed between the central device and the terminal device,
The transmission method conversion device includes:
A first receiver for receiving a UD type transmission system message from the central device;
A first conversion unit that converts a message of the UD type transmission method received by the first reception unit into a message of the transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model;
A first transmission unit that transmits the message of the transmission method for the traffic control system that does not adopt IP in the third layer of the OSI reference model, converted by the first conversion unit, to the terminal device;
A second receiving unit that receives from the terminal device a message of the transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model;
A second conversion unit that converts the message of the transmission method for the traffic control system that does not adopt IP in the third layer of the OSI reference model received by the second reception unit into a message of the UD type transmission method;
E Bei and a second transmission unit for transmitting to the central unit a message UD shaped transmission method which has been converted by the second converter,
The traffic control system, wherein the first conversion unit and the second conversion unit also perform conversion of application data included in a message . A traffic control system comprising a central device for a traffic control system and a plurality of terminal devices installed on the roadside,
The traffic control system is a transmission method having a different application data structure from the central device that communicates with the terminal device in the UD type transmission method, and does not adopt IP in the third layer of the OSI reference model. It is a configuration that includes a plurality of terminal devices that communicate with the central device in a transmission system for a traffic control system,
Further, the traffic control system includes a transmission method conversion device that converts a transmission method interposed between the central device and the plurality of terminal devices,
The transmission system conversion apparatus, to the plurality of terminal devices are respectively connected by separate communication lines, and, for the central unit, are connected by a single communication line,
Furthermore, the transmission method conversion device comprises:
A first reception for receiving a message of a UD type transmission method including a UD type address assigned to each of the terminal devices from the central device via the one communication line for communication with the plurality of terminal devices. And
A first conversion unit that converts a message of the UD type transmission method received by the first reception unit into a message of the transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model;
Based on the UD type address included in the message of the UD type transmission method, a communication line with a terminal device as a transmission destination is selected and selected from a plurality of communication lines connected to the plurality of terminal devices. The message of the transmission method for the traffic control system that does not adopt IP in the third layer of the OSI reference model, which is converted by the first conversion unit, is transmitted to the terminal device that is the transmission destination, converted by the first conversion unit. A first transmitter that
A second receiving unit that receives a message of the transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model from the terminal device via a communication line connected to the terminal device;
A second conversion unit that converts the message of the transmission method for the traffic control system that does not adopt IP in the third layer of the OSI reference model received by the second reception unit into a message of the UD type transmission method;
A UD type address assigned for communication with the terminal device that transmitted the message is added to the message of the UD type transmission method converted by the second conversion unit, and the one communication line is used to e Bei a second transmission unit for transmitting to the central unit, the
The traffic control system, wherein the first conversion unit and the second conversion unit also perform conversion of application data included in a message . The traffic control transmission method for systems, traffic control system according to claim 1 or 2 wherein the M-shaped transmission system not employing the IP in the third layer of the OSI reference model. The terminal device communicates with the central device by the UD type transmission method in addition to the terminal device that communicates with the central device by the transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model. UD type terminal devices are mixed,
When the transmission destination of the message of the UD type transmission method received from the central device or the UD type terminal device is the UD type terminal device or the central device, the transmission type conversion device is the first conversion unit. Alternatively, the received message of the UD type transmission scheme is transmitted to the UD type terminal device or the central unit as the transmission destination without being converted by the second conversion unit.
The traffic control system according to any one of claims 1 to 3. A central device for a traffic control system that communicates with a terminal device using a UD type transmission method, and a transmission method that is installed on the roadside and has a different application data structure from the UD type transmission method. In a traffic control system that includes a terminal device that communicates with a central device in a transmission method for a traffic control system that does not employ IP in a layer, the transmission method is interposed between the central device and the terminal device. A transmission method conversion device for converting,
A first receiver for receiving a UD type transmission system message from the central device;
A first conversion unit that converts a message of the UD type transmission method received by the first reception unit into a message of the transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model;
A first transmission unit that transmits the message of the transmission method for the traffic control system that does not adopt IP in the third layer of the OSI reference model, converted by the first conversion unit, to the terminal device;
A second receiving unit that receives from the terminal device a message of the transmission method for the traffic control system that does not employ IP in the third layer of the OSI reference model;
A second conversion unit that converts the message of the transmission method for the traffic control system that does not adopt IP in the third layer of the OSI reference model received by the second reception unit into a message of the UD type transmission method;
A second transmitter for transmitting a message of the UD type transmission system converted by the second converter to the central device,
The first conversion unit and the second conversion unit also convert application data included in a message.
A transmission system conversion device in a traffic control system. A terminal device that is a transmission destination of the message of the transmission method for the traffic control system converted by the first conversion unit from a plurality of communication lines connected to each of the plurality of terminal devices connected to the transmission method conversion device Control to select the communication line connected to
  The transmission system conversion apparatus in the traffic control system according to claim 5. A UD type terminal device for a traffic control system,
A UD type terminal device having a transmission method conversion function, comprising the transmission method conversion device according to claim 5.

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