JPS63203023A - Packet transmission access system in train radio line - Google Patents

Abstract

PURPOSE:To switch the giving/receiving of transmission right from on-vehicle to on- ground at a high random speed by transferring a transmission request to the on-ground via a connection control line separated from a data line and allowing an on-ground equipment to apply the assignment of an operating channel and the transmission approval. CONSTITUTION:Upon request of a transmission request from an on-vehicle terminal equipment in a general data channel, the assignment of a radio channel and the transmission request are applied in the contention form to a routine data system. On the other hand, the routine data channel transmits the designation of the general data system ratio channel and the transmission approval to a train having a specific constant in the broadcast mode synchronously with the polling period from the on-ground equipment in a direction of the on-vehicle by using a transmission request signal from the on-ground equipment. The on-vehicle terminal equipment making the transmission request looks up a transmission enable and operating channel designation signal sent from the routine data system and sends a packet from the on-vehicle equipment toward the on-ground equipment. Thus, no transmission contention takes place and a data output is attained to the on-ground terminal equipment as soon as a packet transmission ACK is sent tentatively.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention adds an address from the ground to the top of the train, and accesses a specific train in the data broadcasting mode, and from the top of the train to the ground, accesses a wireless channel in the transmission right contention mode. The present invention relates to a packet transmission access method for train radio lines that access trains.

(Prior art) Figures 3 and 4 show, for example, the configuration and transmission control of a general-purpose data system in a conventional train radio communication system shown in Chapter 4 (Train-to-Train Communication System) of "Electronic Control Communication System for Shinkansen" In this system example, a communication method is used in which the start of data communication is discussed over a telephone call, a wireless channel to be accessed is set by polling via a connection control line, and then packet data is transferred, a channel access method using static switching. be.

Furthermore, data communication lines for train radio are generally divided 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 mobile stations, and connection control for general-purpose data systems is performed via fixed data channels.

In the configuration of the general-purpose data system shown in Fig. 5, the data terminal DP
can be connected to the central station C1, the control station T, and the mobile station S, respectively, and a total of 4 radio channels including channels 17 and 1B shown in the figure can be assigned. There is one central station C for the entire system, and control stations T that supervise base stations K of about 1° are placed several times along the line. Central station C and control station T,
A fixed line L1 is connected to the control station T and the base station. L! (wired), and the base station and mobile station S are connected by an LCX (leaky coaxial) wireless line M.

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, during transmission, the train driver DR communicates with the train command DS by phone and uses the vehicle monitor SM (mobile station side terminal).
``Transmission request P,'' is output to the mobile station S data transmission frame by key operation.

The mobile station data transmission rack outputs a "connection request P2" as a response to the polling request of the fixed data system.

In response to this, the central station C data transmission rack issues a “reception request P3” to the command display (central station side terminal) CT, and receives a “reception OK R,” from the command display CT.
” and then again via the fixed data system, select “Connection OK.”
R2" with the address. The mobile station data transmission rack at the address that receives this notification outputs "Sendable R1" to the vehicle monitor SM.

The above sequence completes the line setting between the mobile station vehicle monitor SM and the central station C command display, and from now on E
Screen data and ACK (acknowledgement) nd-to-end
``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," as a response to a fixed data polling request, and the central station C data transmission rack receives this. The line release sequence is completed (EOT: end of text) by simultaneously notifying "release Q2" 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 collecting data periodically or transmitting long data between the same terminals, but In order to apply this method to a so-called bucket transmission system that transmits and receives small amounts of data that occur randomly in time, such as communication between multiple data terminals, it is not possible to randomly switch wireless channels with 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 to solve the above-mentioned problems, and it is a method for transmitting packets on a train radio line that can control transmission rights of radio channels in train radio at high speed and switch randomly at high frequency. The purpose is to provide an access method.

[Means for solving problems]

The packet transmission access system in the train radio line according to the present invention is a transmission path access system from on-board to the ground, where the connection control line and the data line are separated, and a train that wants to send a packet sends a transmission request via the control line. The ground side receives this 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 that will not cause transmission collisions. In addition, if there are no free wireless channels, the ground side will allocate a wireless channel using a predetermined method such as priority, and will not output a transmittable signal to the vehicle.
This allows transmission rights to be given and received from the vehicle to the ground direction randomly and at high speed.

[For production]

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 separate from the data line. Do this. Even if there are transmission requests from different vehicles at the same time, the wireless channel assignment is changed, but transmission approval is not granted at the same time, but transmission is acknowledged after one transmission is completed, thereby preventing transmission collisions. Make it.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In the figure, 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,
, sDt is an on-board transmission device, GDI, GDI is a ground transmission device, 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 P 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 continuous format. On the other hand, in the fixed data channel, on the ground side, the transmission request P4 signal is used to broadcast the designation of a general-purpose data wireless channel and transmission approval R4 to a specific number of trains in synchronization with the boring cycle from the ground to the top of the train. Transmit in mode.

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 data system. P.

Therefore, data can be output to the ground terminal at the same time as the packet transmission "ACK" is returned, even though transmission collisions can occur in principle.

In addition, Figure 2 is a time chart to supplement the transmission sequence in Figure 1.
), it is possible to allocate a general-purpose wireless channel and send out data for transmission approval using a fixed data system at regular intervals, and use the contention method to
When a transmission request is issued as shown in (d) or (e
) respectively indicate that packet transmission is approved on the wireless channel f1.

Also, when the packet transmission is completed on the top side of the vehicle, (b) or (C
By outputting transmission cancellation using the contention method as shown in 1, the ground side assigns the corresponding radio channel f1.
Reset.

Furthermore, FIG. 3 is a time chart when transmission requests occur simultaneously and when there is a vacant wireless channel. A transmission request is made simultaneously from (b) and (C1), and this request is transmitted to the ground side using the contention method. In (d), a packet is sent on radio channel f1, and in (111), a packet is sent on radio channel rt. Indicates approval. Upon completion of packet transmission, ground side wireless channel assignments f1 and f2 are reset using the contention method as shown in (b) or (C).

Next, Figure 4 shows the case where transmission requests occur simultaneously,
This is a time chart when there is no free wireless channel. Transmission requests are made simultaneously from (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 radio channel and approve packet transmission, but since there is no free radio channel, approval for transmission of one of them is put on hold using a predetermined method. In Fig. 4, the transmission request by train 2, that is, (0) in the same figure, is suspended, and as shown in +d) by the transmission request and reception of train 1, train 1 sends a packet, and then train 1 cancels the transmission (from al to Regarding (e), transmission is approved on the wireless channel f1, and the packet of train 2 is sent out.

〔Effect of the invention〕

As described above, according to the present invention, a transmission request is output from the vehicle to the ground through 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 the transmission is started after that, it is possible to exclusively allocate the wireless channel according to the length of the packet, and it is also possible to use the wireless channel effectively without causing wireless channel collisions. There is an effect that can be done.

[Brief explanation of the drawing]

FIG. 5 is a configuration diagram of a general-purpose data system in a conventional train radio communication system, and FIG. 6 is a transmission control sequence diagram in the conventional system. OT is on-board terminal, SD is on-board transmission device, GD
I and GDg are ground transmission equipment, and GT is a ground terminal.

Claims (1)

[Claims] Transmission requests from the ground to the train are sent in broadcast mode with an added address, and transmission requests from the train to the ground are accessed in transmission right contest mode. In the transmission path access method from above to the ground, the connection control line and data line are separated, and the transmission timing is divided into slots of a certain time width, so that when a call request is made from the onboard terminal, the 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 sets the condition that two or more trains do not transmit on the same channel. In the train radio line, the check is performed, and transmission control is performed to transmit the radio channel frequency designation and transmittable signal to the corresponding train in broadcast mode through a connection control line from the ground to the top of the train. Packet transmission access method.