JPH0472419B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention accesses a specific train from the ground to the train in broadcast mode with an added address, and accesses a wireless channel from the train to the ground in transmission rights contest mode. This relates to a packet transmission access method in the train radio circuit to be accessed.

[Conventional technology]

Figures 3 and 4 are examples of the general-purpose data system configuration and transmission control system in the conventional train radio communication system shown in Chapter 4 (Train-to-Train Communication System) of "Electronic Control Communication System for Shinkansen," for example.
This is a communication method in which the start of data communication is discussed over a contact phone, a wireless channel to be accessed is set by polling via a connection control line, and then packet data is transferred, a so-called channel access method using static switching.

Furthermore, data communication lines for train radio are generally classified into two types depending on their purpose: fixed data channels that periodically collect short fixed data, and general-purpose data channels that transmit relatively long data that occurs randomly. , communication connection control for fixed data systems is performed by polling the mobile station,
Connection control for general-purpose data systems will be performed via a fixed data channel.

In the configuration of the general-purpose data system shown in Figure 5, the data terminal DP can be connected to the central station C, control station T, and mobile station S, and a total of 4 wireless channels are allocated, including channels 17 and 18 shown in the figure. It's becoming possible. There is one central station C for the entire system, and several control stations T that supervise about 10 base stations K are placed along the line. The central station C and the control station T, and the control station T and the base station K are connected by fixed lines L ₁ and L ₂ (wired).
A base station K and a mobile station S are connected by an LCX (leaky coaxial) wireless line M.

Also, what is illustrated in the central station C and the control station T is a grid-like line switch, which allows designated ground terminals to be connected to the communication partner according to connection control information via a fixed data channel. Connect to a land line that supports the wireless channel used by the terminal.

Next, the operation of the transmission control sequence of the general-purpose data system vehicle monitor will be explained with reference to FIG.
First, when it comes to transmission, the train driver DR gives train commands.
A "transmission request P ₁ " is output to the mobile station S data transmission frame by key operation on the vehicle monitor SM (mobile station side terminal) while maintaining telephone contact with the DS.

The mobile station data transmission frame sends a “connection request P ₂ ” as a response to a fixed data type polling request.
Output. In response to this, the central station C data transmission rack issues a “reception request P ₃ ” to the command display (central station side terminal) CT, and the command display
After confirming “reception OK R ₁ ” from the CT, it once again notifies “connection OK R ₂ ” with an address via the fixed data system. Upon receiving this, the mobile station data transmission rack at the address outputs "transmittable _R3 " to the vehicle monitor SM.

With the above sequence, mobile station vehicle monitor SM
The line settings between the C command display and the central station C command display have been completed, and from now on, screen data and “ACK
(Acknowledgement)” Signals are transferred to each other.

Once the necessary data transfer is completed, the line release sequence begins. The line release sequence is the same as for line connection; the mobile station data transmission rack outputs a "release request Q 1" as a response to a fixed data polling request, and the central station C data transmission rack that receives this outputs a "release request Q ₁ ". The line release sequence is completed (EOT: end of text) by simultaneously notifying "release Q ₂ " with an address via the fixed data system again, and data transmission between the vehicle monitor and the command display is completed.

[Problem that the invention seeks to solve]

The conventional packet transmission access method for train radio lines is configured as described above, so there is no problem when periodically collecting data or transmitting long data between the same terminals, but on-board and ground In order to apply this method to a so-called packet transmission system in which a small amount of data that occurs randomly in time is exchanged, such as communication between a plurality of data terminals, it is not possible to randomly switch wireless channels at a high frequency. Additionally, there were other problems, such as the inability to control high-speed contention for wireless channel transmission rights.

This invention was made in order to solve the above-mentioned problems, and it is a method for transmitting packets on train radio lines that can control the transfer of transmission rights of radio channels in train radios at high speed and switch them randomly at high frequency. The purpose is to provide an access method.

[Means for solving problems]

The packet transmission access system for train radio circuits according to the present invention is a transmission line access system from onboard to ground, where the connection control line and data line are separated, and a train that wants to send a packet sends a transmission request via the control line. The ground side, which receives the information, checks the current availability of wireless channels and notifies the radio channel from the ground to the top of the vehicle in a designated broadcast mode in a designated broadcasting mode. In addition, if there is no free wireless channel, the ground side assigns a wireless channel and sends a signal indicating that transmission is possible using a predetermined method such as priority, to the onboard direction.
It is designed so that no output is output, and the transfer of transmission rights in the ground direction can be switched randomly and at high speed from onboard the vehicle.

[Effect]

In this invention, the contention control for transmission rights of the train radio line from the onboard to the ground is performed by sending a transmission request from the onboard to the ground through a control line different from the data line, and allocating channels to be used from the ground. Approve transmission. Even if transmission requests are received from different vehicles at the same time, the wireless channel assignments will be changed, but transmission approval will not be granted at the same time, but transmission will be acknowledged after one transmission has finished, thereby preventing transmission collisions. Make it.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same parts as in FIG. 6 are designated by the same reference numerals.In the figure, a general-purpose data channel, which is a data line, and a regular data channel, which is a connection control line, are shown separately. . In the figure, OP is an on-board terminal, SD ₁ and SD ₂ are on-board transmission devices, GD ₁ and GD ₂ are ground transmission devices, and GT is a ground terminal.

Next, the operation will be explained. First, in the general-purpose data channel, when there is a transmission request _P1 from the on-board terminal OT, a wireless channel is allocated and a transmission request _P4 is made to the fixed data system in a contention format. on the other hand,
In the fixed data channel, on the ground side, this transmission request P ₄ signal is used to designate a general-purpose data radio channel and send transmission approval R ₄ to a specific number of trains in broadcast mode from the ground to the train in synchronization with the polling cycle. Transmit.

The on-board terminal OT that has made the transmission request _P1 sends a packet from the on-board to the ground in response to the transmission permission and usable channel designation _R4 signal sent in the fixed form data system. P ₅ Therefore, in principle, transmission collisions cannot occur, and data can be output to the ground terminal at the same time as the packet transmission "ACK" is returned.

Fig. 2 is a time chart to supplement the transmission sequence in Fig. 1. In the fixed data channel, as shown in Fig. 2 a, general-purpose wireless channel allocation and transmission approval are performed at regular intervals in the fixed data system. When a transmission request is issued using the contention method as shown in b or c in the same figure, the wireless channel is assigned to d or e, respectively.
_f1 indicates that packet transmission is approved.

Furthermore, when the transmission of the packet is completed on the on-board side, transmission cancellation is outputted using the contention method as shown in b or c, and the corresponding radio channel allocation _f1 is reset on the ground side.

Furthermore, FIG. 3 is a time chart when transmission requests occur simultaneously and when there is free space on the wireless channel. Transmission requests are made simultaneously from b and c in the figure, and these requests are transmitted to the ground side using the contention method, and packet transmission is approved to d on wireless channel f ₁ and e on wireless channel f ₂ . Show that. Upon completion of packet transmission, the ground side wireless channel assignments f ₁ and f ₂ are reset using the contention method as shown in b or c.

Next, FIG. 4 is a time chart when transmission requests occur simultaneously and when there is no free wireless channel. Transmission requests are simultaneously made from stations b and c in the figure, and are transmitted to the ground side using the contention method. On the ground side, an attempt is made to allocate a wireless channel and approve packet transmission, but since there are no available wireless channels, approval for transmission of either one is put on hold using a predetermined method. In Figure 4, the transmission request by train 2, i.e., c in the figure, is suspended, and the transmission request and reception of train 1, as shown in d,
Train 1 sends a packet, and then train 1 cancels the transmission, and transmission is approved from a to e on radio channel _f1 , and train 2's packet is sent.

〔Effect of the invention〕

As described above, according to the present invention, a transmission request is output from the vehicle to the ground using a connection control line separate from the data line, and wireless channel allocation and transmission approval are performed from the ground to the vehicle. Since transmission is started after that, it is possible to exclusively allocate a wireless channel according to the length of the packet, and it is also possible to use wireless channels effectively without causing wireless channel collisions. There is an effect that can be done.

[Brief explanation of the drawing]

Fig. 1 is a sequence diagram of transmission control showing an embodiment of the present invention, Figs. 2 to 4 are time charts to supplement Fig. 1, and Fig. 5 is general-purpose data in a conventional train radio communication system. A system configuration diagram, FIG. 6, is a transmission control sequence diagram in a conventional system. OT is on-board terminal, SD ₁ and SD ₂ are on-board transmission equipment,
GD ₁ and GD ₂ are ground transmission equipment, and GT is a ground terminal.

Claims (1)

[Claims] 1 Transmission requests from the ground to the train are sent in the broadcast mode with an added address, and transmission requests from the train to the ground are accessed in the transmission right contest mode. The transmission line access method from onboard to the ground separates the connection control line and data line, and divides the transmission timing into slots of a certain time width, so that when a call request is made from the onboard terminal, the connection control line and data line are separated. The train that corresponds to the call request transfers the transmission request from the train to the ground via the connection line, and the ground station that receives the transmission request checks the availability of the radio channel and makes sure that two or more trains do not transmit on the same channel. A train radio line characterized in that a condition check is executed and transmission control is performed to transmit a frequency designation of a radio channel and a transmittable signal to the relevant train in a broadcast mode through a connection control line from the ground to the top of the train. A packet transmission access method in