JP2825033B2 - Train wireless communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system for trains, and more particularly to a radio communication system for trains, which communicates with a train moving at high speed on a track by using radio relay transceivers arranged at substantially equal intervals on the track. The present invention relates to a train radio communication system that moves while communicating.

[0002]

2. Description of the Related Art Conventionally, this type of train radio communication system employs a base station device 1 as shown in FIG.
The transmission / reception devices 10A to 10A which are arranged at approximately equal intervals along the railroad track, for example, by radio or the like between the 00 and the train 200.
C are distributed and transmitted as radio waves 2A to 2C and 3A to 3C using different uplink frequencies f1 and f3 and downlinks f2 and f4 for uplink and downlink respectively. The trains 200 on the track have their radio waves 2A-2C, 3A-
Transmitter / receiver 10A to 10C using the transmitter / receiver 20
Was communicating with The use frequency is changed for each section in order to prevent radio wave interference between the sections.

[0003]

In the conventional train radio communication system described above, the train transceiver 20 sequentially switches the transmission and reception frequencies of each radio section as the train 200 moves from the section C to the section A. There is a need. Therefore, the transceiver 20 of a train moving at a particularly high speed needs to use, for example, a synthesizer capable of high-speed retraction, or to have local oscillators corresponding to the number of frequencies used. In addition, when switching through sections, control of instantaneous interruption or signal continuity, or use of an antenna with a special radiation pattern to eliminate the dead zone of radio waves, or certain specific sections become obstacles There was a problem to be solved, such as construction of a rescue system at the time.

[0004]

SUMMARY OF THE INVENTION A train radio communication system according to the present invention comprises a transceiver which is arranged in a plurality of ground sections to form a radio relay line, and a base station which transmits or receives a burst signal to or from these transceivers. Between the plurality of transceivers so that the base station transmits and receives a burst signal between the transceiver and the train transceiver that moves on the ground section via the transceiver.
A transmission frequency signal and a reception frequency signal used at the same frequency for a fixed trunk line are transmitted and received for the train.
Train radio communication system used between the transmitter and the transceiver
Wherein each of said transceivers is a preceding transceiver
Received and decoded from the burst signal
Given the maximum occupation time and equal to or long delay time t ₀
It has a delay circuit for sending it to the subsequent transceiver.

[0005]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of one embodiment of the present invention, FIG. 2 is an explanatory diagram of a time sequence of a burst signal in each section of the embodiment,
FIG. 3 is an explanatory diagram of a signal format in a burst signal. First, in FIG. 1, in the base station 300, a continuous signal 5 to be transmitted is converted into a burst signal of a fixed period by a burst conversion circuit 301, and each of the transmitting and receiving apparatuses 30A to 30C, 31A-31
In order to distribute the signal 7 to C, the signal 7 is sent to the transceiver 30A through the distributor 302. Transceiver 30A transmits as a burst wave using frequency f1. In the game in the section A, the transceiver 31A reproduces the received signal 8A,
After delaying by A for a fixed time t0, the signal is transmitted again in a burst to the next section B via the transmission / reception device 30B. The signal is sequentially distributed to each section on the orbit by this repetition, and the transceivers 30A, 30B, and 31A,
The transceivers 50 for B, C and the train use a pair of radio frequencies f1 / f1A. However, the train transceiver 50
The transmission and reception are opposite to each other with respect to the fixed radio frequency of the transceiver. In this case, the transmission timing of the transmitter in the base station and the delay time in the relay station are controlled so that the burst waves in each section do not overlap.

The time sequence of the burst signal will be described with reference to FIG. The horizontal axis of FIG.
B is located at a distance L in sections A, B, and C. The vertical axis represents time. Taking the transceiver 30A as an example, burst signals S3, S4, and S5 are transmitted at time intervals of t1. Here, the time t1 is the burst transmission time τ and the distance L
Is set at a time interval slightly longer than the time corresponding to the sum of the radio wave propagation time T. In the next section, the received signal is delayed by the time t0 and relayed and transmitted again to the next section. As described above, assuming that each burst signal propagates as time t elapses and it takes time T to propagate the distance L, if T + τ is greater than t1, the bursts transmitted by each transmitter overlap in the next section. Never. Furthermore, if the distance L, the burst length τ, and the repetition period t1 are selected, it is possible to make them overlap only at a sufficiently long distance due to attenuation by radio wave propagation. The transceivers 30B, 30C, 30
D shows a state where the burst signals S2, S1 and S0 are being received, respectively.
A transmits the burst signal S3 from the transceiver 30B,
An additional description will be given of the operation of retransmitting data with a delay of time interval t0 in transceiver 30C. First, the burst signal S
In No. 3, the burst signal S3A is received by the transceiver 31A after the elapse of the propagation time T. Here, the delay circuit 40A receives a delay of time t0, and outputs the burst signal SCB as the burst signal SCB.
0B. The transceiver 31B receives the burst signal S3B and outputs a burst signal S3C. Similarly, the transceiver 31B receives a delay of time t0 in the delay circuit 40B and outputs the burst signal S3C.
3D is transmitted from the transceiver 30C. Next, a state in which the transceiver 50 of the train receives radio waves from the transceivers 30B, 30C, and 30D of the fixed station will be described. The radio wave X of the train has the same frequency f as that of the fixed transceivers 30A to 30D as described above.
Since 1,1a is used, radio waves in any section can be always received. For example, near the boundary between sections B and C, there is a possibility that both the transceivers 30C and 30B will receive radio waves. Now the transmission burst signal S of the transceiver 30C
If 2B is received at the time of the reception burst signal R2B, even if the radio wave from the transceiver 30B is also received at the same point Y, the transmission burst signal S2A has a time difference of t0. I will not do it.
Similarly, when receiving the reception burst signal R3B of the radio wave of the train, the radio wave attenuated by the transmitter / receiver 30A may be received. There is no.

Next, an application example of the present invention will be described.
As described above, since the radio wave X of the train uses the same frequency, there is a possibility that a plurality of fixed transceivers will receive transmission burst signals. That is, the train transceiver 50
Receives the transmission burst signal S3B of the transceiver 30B as the reception burst signal R3B and can receive the transmission burst signal S3 of the transceiver 30A as the reception burst signal R3A with a delay of t0. Therefore, for example, when the transceiver 30B fails and the reception burst signal R3B is not received, the transmission burst signal S3 of the transceiver 30A can be received as the reception burst signal R3A. In principle, if you become a lower station, you can receive as many as the upper transceivers,
Due to the attenuation of the radio wave, the burst signal of the upper transceiver can be demodulated in the range of 2 to 3 hops to perform the alternate reception of the opposite transceiver.

Next, the signal format of the burst signal used here is, as shown in FIG.
Overhead bits (OH
Bit), a rank signal indicating the temporal rank of the burst, a check bit for checking the presence or absence of a burst error, and main signal data. Since the train 200 can sequentially move while receiving a plurality of burst waves of the same frequency, the transmitter / receiver 50 of the train 200 demodulates the received bursts of a plurality of children and checks for errors added to each burst. By looking at the signal indicating the rank of the burst, one of the bursts having the same rank is selected, and is converted into the continuous signal 13 by the burst / continuous signal conversion circuit 51.

Conversely, transmission from the train 200 similarly transmits signals in bursts using the frequency f1A, and the transceivers 30A, 30B, 30C on the track sequentially relay the reception and transmit the signals to the base station 300. I do. The base station 300 checks the error of the received data of each received burst signal 7 input to the distributor 302, selects a signal based on the signal indicating the burst order, and selects a signal based on the signal. It can be output as received data 5.

[0010]

As described above, according to the present invention, the train transceiver on the track transmits and receives to and from the fixed transceiver using the same pair of frequencies. Therefore, the transmitter / receiver of the train does not need to switch the frequency, so that the instantaneous interruption of the signal can be eliminated each time the train passes through each section. Also,
In a certain section, there are many similar signals from adjacent sections other than the signal of the own section. Therefore, even if a failure of the transceiver in the section occurs, it can be easily remedied by adjacent or other signals. is there. Therefore, the present invention is also effective in relieving an error due to a propagation failure or noise.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a time chart of a burst signal for explaining the embodiment.

FIG. 3 is a signal format illustrating the embodiment.

FIG. 4 is a configuration diagram of a conventional train wireless communication system.

[Explanation of symbols]

 100, 300 base station 200 train 10A, B, C, 30A, B, C transceiver 20, 50 train transceiver 40A, B, C delay circuit 51, 301 burst conversion circuit 302 distributor

Claims (2)

(57) [Claims] 1. A transceiver which is arranged in each of a plurality of terrestrial sections and forms a wireless relay line, a base station which transmits or receives a burst signal to or from these transceivers, and wherein the base station is connected to the ground via the transceiver. said transmission frequency signal and reception frequency signal is used in the same frequency in the trunk line of the fixing between the between the plurality of transceivers to transmit and receive burst signals between the trains for transceivers moving the section train
Train radio used between the transceiver for transmission and the transceiver
In the communication system, each of the transceivers is a
The burst signal received from the receiver and decoded
Delay time equal to or longer than the maximum occupation time of the
There is a delay circuit that gives t ₀ and sends it to the subsequent transceiver
Train radio communication system, characterized in that that. 2. The system according to claim 1, wherein the train transceiver is moving from at least two of the transceivers present in a plurality of ground sections .
When the transmission signal is received and the decoded burst signal is delayed
Train radio communication system according to claim, wherein further comprising means to avoid the identified interference by between t _0.