JP2545860B2 - Train radio system - Google Patents

Description

TECHNICAL FIELD The present invention relates to a train radio system, and more particularly, to a train radio system that communicates between a mobile station in a train and a radio relay station along a train track by using frequencies in the microwave band or higher. Regarding the system.

Conventional technology There is no commercialization example of train mobile communication systems using radio frequencies in the microwave band or higher in Japan.
Radios transmitting / receiving 1, f1 ′ and radios transmitting / receiving frequencies f2, f2 ′ (for example, f1, f2 are from the repeater to the mobile station, f1 ′,
f2 'is the opposite frequency). Multiple radio repeaters are installed along the train track, with the antennas placed back to back, and the mobile stations (for example, telephones) installed in trains There is a train radio system that relays with the telephone exchange. In such a wireless system, there is a drawback that communication is cut off when the wireless device of the wireless repeater fails because of a dead zone (a region where the electromagnetic wave does not reach) of an electric wave when it is extremely close to the wireless repeater.

This will be described in detail with reference to the drawings. FIG. 5 is an example of a train radio system using a radio repeater in which a pair of antennas are arranged back to back. In FIG. 5, wireless repeaters a, b, c, ...
... is the installation distance (several 100m to several tens of K depending on the frequency band used)
m) is installed at one of the frequencies f1, f of the wireless repeater.
1'and the other frequency f2, f2 'covers the radio repeater to form the radio wave area, and the train-mounted mobile station sets one frequency f1, f1' and the other frequency f2, f2 '. Communication becomes possible by switching for each section.

However, as shown in FIG. 6, in the train radio system of FIG. 5, when the mobile station approaches the radio repeater, the dead zones D1, D2 ,. There may be a momentary interruption in wireless zone switching →→ ……. As a prominent example of this, switching of the wireless zone when the wireless device of the wireless relay device fails as shown in FIG. 7 will be described.

In Fig. 7, switching of wireless zones is normal when
→ ……. Here, for example, when a wireless device that constitutes a zone fails, even if the zone is continuously used to rescue the zone, a momentary interruption occurs in the vicinity of the wireless relay device c that is normally covered by the radio waves of the zone. . Similarly, if a wireless device forming a zone fails, a momentary interruption occurs near the wireless relay device b.

SUMMARY OF THE INVENTION Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to eliminate a dead zone of radio waves in the vicinity of a wireless repeater and Another object of the present invention is to provide a train radio system in which a momentary interruption in the vicinity of the radio repeater does not occur even when the train fails.

According to the present invention, a plurality of wireless relay stations having a pair of wireless transceivers in which a pair of antennas are arranged back to back are installed along a train line, and the directivity of each of these antennas is set to the facing direction. A train radio system configured to relay between a mobile station and a fixed station in a train by covering each dead zone of radio waves in the vicinity of the pair of antennas corresponding to its own relay station. A train radio system is obtained which has respective auxiliary radio zones that operate.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a system block diagram of one embodiment of the present invention. In the figure, a plurality of wireless repeaters are installed along a train line, and each of these wireless repeaters has a pair of wireless transceivers A and B having antennas C and D arranged back to back. are doing. Between the pair of antennas C and D, for example, a trumpet-shaped electromagnetic horn E is provided, respectively. The electromagnetic horn E is used to repair and compensate the dead zone of the radio wave near the radio transceivers A and B. It has become.

FIG. 2 shows an example of the pattern of the radio wave zone in each repeater of FIG. The radio repeater uses different frequencies f1, f1 'and f2, f2' (for example, f1 and f2 are used in the direction from the radio repeater to the mobile station, and f1 'and f2' are used in the opposite direction). As a result, the wireless zones 11 and 12 having a so-called pencil beam-like directivity are formed.

On the other hand, the electromagnetic horn E forms an auxiliary wireless zone 13 for compensating for the dead zone of the radio wave existing in the vicinity of the wireless repeater, whereby the dead zone is relieved over the entire section. .

In such a configuration, switching of the wireless zone in the normal state is performed as →→→ .... However, in each area immediately below the wireless repeater, the auxiliary wireless zone from each electromagnetic horn is switched to.

Here, when one wireless device A of the repeater fails,
However, the zone can be continuously used as a relief of the zone, and the radio wave of the zone from the electromagnetic horn E can be used in the vicinity of the repeater. Further, when the wireless device B fails, the zone is lost, but the zone can be used earlier to rescue this zone, and the zone from the electromagnetic horn E can be continuously used near the repeater.

FIG. 3 is a block diagram of another embodiment of the present invention. Each wireless repeater has a horizontal omnidirectional antenna F instead of the electromagnetic horn E of FIG. This is an example of trying to compensate for the dead zone of the radio wave near the repeater by the flexible antenna F. In this case, the zone switching is performed because the zone by the third antenna F is added in addition to the zone of the pair of antennas A and B of the repeater.
(A) →→→ (b) →→ ...

FIG. 4 shows a pattern example of the radio wave zone in each relay in the case of FIG. The auxiliary zone which is the radio wave zone 14 by the antenna F uses the third frequency pair f3 and f3 '.

Also in this case, the same operation as in the embodiment of FIG.
Since the dead zone of the radio wave near each repeater can be rescued,
Even if the transceiver fails, it is possible to prevent instantaneous interruption of radio waves.

In the second embodiment, the omnidirectional antenna is used as the antenna F, but it is obvious that the directional antenna may be used to form the auxiliary radio wave zone.

As described above, according to the present invention, since the dead zone of the radio wave generated in the vicinity of the wireless repeater is covered, it is possible to increase the frequency of the repeater to form a duplex configuration without increasing the frequency of the repeater. There is an effect that it is possible to suppress the instantaneous interruption of communication caused by a failure.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a wireless zone configuration of the example of FIG. 1, FIG. 3 is a diagram showing another embodiment of the present invention, and FIG. The figure which shows the radio zone structure of the example of FIG. 3, and FIGS. 5-7 is a figure for demonstrating a train radio system. Explanation of main part code A, B …… Transceiver C, D …… A pair of antennas E …… Electromagnetic horn F …… Antenna

Claims (1)

(57) [Claims] A plurality of wireless relay stations having a pair of wireless transceivers in which a pair of antennas are arranged back to back are installed along a train track, and the directivity of each of these antennas is set in the in-game direction. A train radio system for relaying between a mobile station and a fixed station, each of the relay stations being an auxiliary radio zone that covers a dead zone of radio waves in the vicinity of the pair of antennas corresponding to its own relay station. A train radio system, characterized in that each has.