JPS6230442A - Train radio communication system - Google Patents

Abstract

PURPOSE:To access radio channels at high speed, high frequency and at random by informing simultaneously busy state of data circuits at a short period according to an output of a carrier detecting circuit provided in a ground station through a fixed form data circuit. CONSTITUTION:In a fixed form data circuit, the presence or absence of carrier of a general purpose data circuit is transmitted repeatedly in a broadcasting mode in the direction from ground to a train according to an output of a carrier transmitting circuit of a general purpose data circuit provided in a central station 1 and a base station 3. On the other hand, in the general purpose data circuit, when a transmission request signal is generated from the terminal equipment of a mobile station, bucket is sent out in the direction from the mobile station 4 to a ground station (a central station 1, a control office 2, a base station 3) using a wireless channel which is not busy according to channel busy information sent periodically by the fixed form data circuit. At this time, as the ground station is monitoring the presence or absence of carrier of the general purpose data circuit, it is possible to inform the presence or absence of carrier in the radio channel simultaneously and at a short period.

Description

[Detailed Description of the Invention] [Field of Application for R Overhead 1] The present invention relates to a train radio communication system, and in particular, the radio direction from a ground station to a mobile station of each train is broadcast in a broadcast mode with an address attached and is not in a specific area. access columns JT,L,
The radio direction from the mobile station to the ground station relates to a system that accesses the radio channel in a contention mode and performs bucket transmissions.

[Conventional technology 1 Conventionally, as a bucket data transmission system using train radio, for example, there is a Communication Systems, pp. 133-142)
As shown in Figure 2, after discussing the start of Day 2 communication via a contact phone and setting up the wireless line to be accessed by polling via the fixed data line that is the connection control line, static switching is performed to transmit bucket data. There was a channel access method based on

Normally, data communication lines for train radio are classified into two types depending on their use: fixed data lines that periodically collect short fixed data, and general-purpose data lines 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 data systems is performed via fixed data lines.

The fjS4 diagram and the fpJ5 diagram are shown in the above-mentioned document, and respectively show the configuration of a general-purpose data system and an example of a terminal device transmission control sequence in a conventional train radio communication system.

In FIG. 4, a data terminal device can be connected to a central station 1, a control station 2, and a mobile station 4, respectively, and a total of four radio channels are assigned, including channels c b 17 and e ++ 18 shown in the figure. It is possible fffi. One central station 1 is placed in every system, and several control stations 2 that supervise about 10 base stations 3 are placed along the route and are supervised by the central station 1. The central station 1, the control station 2, and the base station 3 are connected by a fixed dedicated data line #i (wired), and the connection between the base station 3 and the mobile station 4 is as follows.
1. It is connected by a cX (leaky coaxial) wireless line.

In addition, the central station 1, control station 2, and base station 3 are terrestrial (fixed)
The mobile station 4 is also referred to as an on-vehicle station.

Illustrated in the central station 1 and control station 2 are grid-shaped line switches as data transmission racks 1a and v2a, respectively, which perform connection control 1. through fixed data lines. +?
In response to the notification, the central office terminal equipment raT of the designated central office 1
G or control station 2 ground terminal device (not shown) is connected to the ground line corresponding to radio channels ch17 and c++18 used by the mobile station terminal device Vt (not shown) with which it communicates. It is.

Next, using the general-purpose data system shown in Figure 4 as an example, the vehicle monitor, that is, the operating status of the train and the operating status of each vehicle's equipment will be displayed on the display in the driver's cab as shown in Figure 5. The transmission control sequence of the mobile station terminal device that supports the treatment will be explained. During transmission, the vehicle driver, while in telephone contact with the train dispatcher, sends a "transmission request" signal to the data transmission rack 4a of the mobile station 4 by key operation (CTC key press fi) on the vehicle monitor, that is, the terminal device on the mobile station side. Sent.

The data transmission A4a of the mobile station 4 outputs a "connection request" signal (the thick arrow indicating this signal represents a fixed data line) as a response to the fixed data type polling request. On the data transmission rack 1a of the central station 1, which receives this, the terminal equipment on the central station 1 side, such as a command display,
Outputs a "reception request" signal to Tg, then inputs and confirms the "reception OK" signal from the terminal device Tg, and sends a "connection OK" signal with an address all at once via the standard data line again. The mobile station 4 side is notified. The data transmission rack 4a of mobile J:J4 having received this sends a "sendable" signal to the mobile station terminal device.

Now that the In+ circuit a setting with the station terminal Tg has been completed, the screen data and the "80K (t'r constant response)" signal will interact end-to-end as shown in the figure. be transferred.

When the necessary data transfer between the two terminal devices is completed, the sequence for releasing the line to the dog begins. The line release sequence is the same as the above line setting, and by pressing the clear key on the mobile station terminal HR, an EOT (end of text) signal is sent to the mobile station 4, and the data transmission rack 4a of the mobile station 4 In response to a polling request on a fixed data line
A "release request" signal is output to the central station 1, and in response to this, the data transmission rack 1a of the central station 1 releases the line by once again notifying the "release" signal with an address via the regular data line. The sequence is complete.

This completes the data transmission between the terminal devices, that is, between the vehicle monitor and the command display.

[Problems to be solved by the invention] Since the conventional system is configured as described above, it is difficult to collect data periodically, or when data is collected between the same terminal devices.
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In order to apply it to a so-called bucket transmission system that exchanges a small amount of data that occurs randomly over time, such as communication between multiple data terminal devices of a ground station, (1) There were problems such as (2) inability to perform high-speed control over contention for wireless channel transmission rights;

The present invention has been made to solve the above-mentioned problems, and provides a bucket transmission line access system that can control transmission rights transfer of radio channels in train radio at high speed and can switch randomly at high frequency. The purpose is to obtain.

Means for Solving Problem E 1 In order to achieve the above object, the train wireless communication system according to the present invention connects as a bucket transmission path access method in the direction from the mobile station on the train to the ground station. A means for separating a regular data line, which is a control line, and a general-purpose data line, which is a data line, and by which the ground station divides the timing of the second radio direction into slots of a fixed time width, and the presence or absence of a carrier for each radio channel. means for detecting a
and means for simultaneously notifying the mobile stations of the situation, and means for each mobile/station to start bucket transmission in the second radio direction via the general-purpose data line in synchronization with the slot using a non-Pino channel. It is characterized by

[Function] In the train radio communication system of the present invention, the transmission right dispute in the direction from the mobile station to the ground station is controlled by a connection control line that is separate from the data line, and the presence or absence of a carrier of a radio channel detected at the ground station is controlled. is repeated at short intervals as a channel busy status, and is notified all at once in broadcast mode, allowing the mobile station to know free channels without delay, and switching transmission path access from mobile station to ground station randomly and at high speed. That's what I do.

[Embodiment] An embodiment of the wireless communication system according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram schematically showing the train wireless communication system of the present invention. In addition to the conventional example shown in FIG. 4, FIG. The central station 1 is provided with a circuit 3a for detecting the carrier, and a circuit 1b for transmitting the presence/absence of the detected carrier to the mobile station 4.

In the transmission control sequences shown in PJ2 diagrams (a) and (b), a general-purpose data line, which is a data line, and a regular data line, which is a connection control line, are shown separately. In the fixed data line, the presence or absence of a general-purpose data line carrier is determined every time polling is performed in the broadcast mode from the ground to the onboard direction according to the output of the carrier transmission circuit 1b of the general-purpose data line provided in the central station 1 and the base station 3. is being transmitted repeatedly.

On the other hand, in a general-purpose data line, when a "transmission request" signal is generated from a mobile station terminal (not shown), a non-busy radio channel is used based on channel busy information that is periodically notified on a fixed data line. Then, a bucket is sent from the mobile station 4 toward the ground station (comprised of the central station 1, the control station 2, and the base station 3). At this time, since the local J-station monitors the presence or absence of a carrier on the general-purpose data line, it is possible to notify all at once in a short period whether or not there is a carrier on that radio channel.

Figure 2 (,) shows the case where there are no buckets sent to the same radio channel at the same time, that is, there is no collision, and the ground station receives the packets correctly and immediately receives 8 CKs (1
At the same time as sending back the ``r constant response)'' signal, data is output to the terminal equipment of the ground station (the terminal equipment Tg of the central station 1, the terminal equipment rrL (not shown) of the control station 2).

On the other hand, Fig. 2 (1) shows a case where, during the first bucket transmission, there is also a bucket transmission from the mobile station 4 of another train using the same radio channel, that is, a transmission collision occurs. The signal is not being received correctly by the ground station. In this case, the mobile station does not receive a response from the two local stations even after waiting for a predetermined period of time, so it retransmits the same bucket after the timeout period has elapsed. The figure shows a case where during retransmission, no transmission collision occurred and the data was correctly received, so an "80K" signal was returned and the data was output to the ground station terminal device.

The reason why the carrier is detected on the ground station side instead of the mobile station is that if the carrier is detected on the mobile station side, the mobile station side will need to have a reception function for all radio channels in the direction from the mobile station to the ground station for all trains.

FIG. 3 shows a time chart for supplementary explanation of the above transmission control sequence. As shown in Figure 13 (a), the standard data line transmits the wireless channel status of the general-purpose data line from the ground station to the mobile station at regular intervals, and all trains within the area must receive this. Therefore, each train detects and uses a non-Pino radio channel to transmit bucket data in response to a "transmission request" signal.

In FIGS. 3(b) and (c), since no carrier is detected in the wireless channel pinot situation ■ shown in FIG.
The case is shown in which trains 1 and 2 both send buckets using channel number r, and a transmission collision occurs and the packets are retransmitted after a timeout.

In this case, as shown in the channel busy situation (2) in FIG. 3(a), the status ``busy'' is notified from the ground station to the mobile station all at once in the broadcast mode. In addition, in Figure 3(d), the queue member 3 who has confirmed ``1r2 ready'' in the channel busy situation ■ of Figure 3(a) uses the wireless 7-wire channel f2 to create consecutive buckets corresponding to long data. In this case, the channel pinot shown in Fig. 3 (,) is shown.
As in situation (2), "f2 busy" is notified all at once to the mobile stations in broadcast mode.

In the above embodiment, the mobile station of each train arbitrarily uses a wireless channel that is not busy in response to the channel busy 4f1 notification that is notified all at once in broadcast mode via a fixed data line. By specifying a wireless channel for each column using a fixed data line, it is possible to prevent transmission collisions from concentrating on a specific channel.
Furthermore, during times when the number of trains on the line within the area is less than the number of radio channels, access can be made without collision.

[Effects of the Invention] As described above, according to the present invention, in accordance with the output of the carrier detection circuit provided at the ground station, , the status of data lines is notified all at once in short cycles, so wireless channels can be used at high speed, high frequency,
Moreover, it has the effect of being able to be accessed randomly.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the train wireless communication system according to the present invention, and FIG. 2 (,) and ([,) are t5
Figure 1 is a diagram explaining the transmission control sequence of the system of the present invention, Figures 3 (n) to (d) are time chart diagrams supplementary explanation of the sequence of Figure 2, and Figure 4 is a diagram explaining the transmission control sequence of the system of the present invention. General-purpose data system configuration diagram, and the fifth
The figure is a diagram illustrating a transmission control sequence in a conventional train wireless communication system. 1: Central station, lb=transmission circuit, 2: Control station, 3: Base station, 3a: Detection circuit, 4: Mobile station, 8: Terminal device. show.

Claims (3)

[Claims] (1) The first radio direction from the ground station to the mobile station of each train is accessed in broadcast mode with an added address, and the second radio direction from the mobile station to the ground station is accessed in the radio channel in transmission right contention mode. In the train radio communication system to be accessed, the ground station includes means for dividing the timing of the second radio direction into slots of a constant time width, means for detecting the presence or absence of a carrier for each of the radio channels, and a means for detecting the presence or absence of a carrier for each radio channel. means for simultaneously notifying the mobile stations of the result as a radio channel busy status in the first radio direction via the fixed data line, and each mobile station synchronizes to the slot using a non-busy radio channel. and the second data line via a general-purpose data line separated from the fixed data line.
A train wireless communication system characterized by comprising means for starting bucket transmission in a wireless direction. (2) The train radio communication system according to claim 1, wherein the ground station is comprised of a central station, a control station, and a base station. (3) The train wireless communication system according to claim 1 or 2, wherein the wireless channel is specified in advance for each train by the fixed data line.