JP2003324377A - Car, car antenna and train radio communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a car antenna and a radio communication system for solving the problem that an incommunicable area occurs due to the influence of a delay wave of each antenna and interference among respective antennas or that radio waves radiated by the respective antennas are combined to distort a waveform when a plurality of antennas are installed in a car. <P>SOLUTION: The plurality of antennas installed in the car direct the center of the radio waves radiated from each of the plurality of antennas toward windows of the car to form an optional angle θ between the center line of the directed radio waves and a normal line, suppressing the occurrence of a delay wave of each radio-frequency radiation from the plurality of antennas. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna installed in a metal casing and a wireless communication system, and more particularly to an antenna device for a vehicle inside a railroad car such as a subway train or a bullet train and a wireless communication system using the same. Is.

[0002]

2. Description of the Related Art Conventionally, as a technique for distributing information in a train to an information terminal in a train, Japanese Patent Laid-Open No. 2001-63580.
There is an "in-train information providing system", which is an in-train information providing system capable of providing information over a wide area within a train. In such a conventional technique,
In many cases, the housing of the vehicle is constructed with the property of reflecting radio waves such as metal, and in order to suppress the influence of radio wave reflection, etc., a radio wave absorber is installed inside the vehicle, or an adaptive transmission / reception antenna or adaptive antenna is used. It was necessary to reduce the influence of reflected radio waves by using a wireless transceiver that performs a typical decoding operation.

FIG. 10 shows a conventional antenna inside a vehicle and an explanatory view of its radio wave radiation. FIG. 10 (1) is a sectional view of the vehicle, FIG. 10 (2) is a top view of the vehicle, and FIG. 10 (3) is an antenna. FIG. 10 (4) is a schematic diagram of waveforms of multiple delayed waves in which radiation from the antenna is reflected on both side surfaces of the vehicle, and FIG. Figure 1
Reference numeral 0 indicates a railroad vehicle such as a Shinkansen, in which a vehicle housing, which is a passenger compartment, is arranged above the wheel portion, and a plurality of windows are attached to the side surface of the vehicle. In FIG. 10 (1),
A general omnidirectional antenna is installed near the ceiling, and when radiating radio waves from this antenna, omnidirectional radiated radio waves, so-called reflected waves, are generated and reflected on the floor and ceiling, the right wall surface and the left wall surface, Multiple delayed waves are generated as multiple reflections due to multiple passes. In FIG. 10C, a schematic diagram of the waveforms of the policy radio wave and the multiple delay wave is shown with the vertical axis representing the received power and the horizontal axis representing the time. For example, assuming that the distance between the ceiling and the floor and the distance between the right wall surface and the left wall surface are 3 m, the first reflected wave from the antenna radiation appears 30 ns later, the next reflected wave appears 60 ns later, and the next 90 ns later. It appears with almost no decay. FIG. 10 (2) shows a case where the radio wave radiated under the same conditions as described above is reflected not only on both side surfaces of the vehicle but also in the longitudinal direction (front and rear) of the vehicle. Assuming that the distance between the front wall surface and the rear wall surface in the longitudinal direction of the vehicle is 25 m, the first reflected wave from the direct radiation from the antenna appears after 170 ns, as shown in the waveform schematic diagram of (4). , The next reflected wave appears at 340ns,
Next, it appears after 510 ns without much attenuation.

In a closed space of a metal housing such as the above-mentioned vehicle, the radio waves radiated from the antenna are hardly attenuated.

[Equation 1] It is known that a delayed wave appears with a delay of t after being moved by a distance c where the length of a room in a closed space is L in a form proportional to and reflected by a wall inside the housing. When the delayed wave appears, the direct radio wave from the antenna and the delayed wave are combined, and the waveform is distorted. As a result, there is a problem that an error occurs in the transmitted data or the communication environment is deteriorated such that communication is interrupted.

Therefore, in order to cope with the phenomenon that the communication environment is deteriorated, a radio wave absorber is placed inside the vehicle casing to reduce reflected waves, and an adaptive antenna or radio is used.
Various measures are needed. However, the electromagnetic wave absorber is expensive, and the work of stretching the electromagnetic wave absorber is troublesome, and the tension of the electromagnetic wave absorber further narrows the inside of the housing. Further, the adaptive transmitting / receiving antenna is also expensive, and it is necessary to mount active parts on the site where the antenna is installed, which causes maintenance work. Also, in the case of a transceiver that performs an adaptive decoding operation, since expensive parts such as a DSP (digital signal processor) are built in, the radio itself becomes expensive.

Next, the case where a plurality of antennas are installed in the vehicle will be described. FIG. 11 is a cross-sectional view of a vehicle when an antenna is installed in a conventional vehicle.
(1) is a side sectional view of a vehicle equipped with an omnidirectional antenna,
FIG. 11 (2) is a side sectional view of the vehicle in which the directional antenna is installed. FIG. 12 is a waveform diagram showing the relationship between the attenuation of radio waves radiated from a conventional antenna in a vehicle and the distance in the vehicle. FIG. 12 (1) shows the case of only the antenna X (or the antenna X ′). Waveform of FIG. 12 (2) is the waveform when only the antenna Y (or antenna Y ′) is used.
(3) is a waveform when the antenna X (or the antenna X ') and the antenna Y (or the antenna Y') emit radio waves in the same phase, and FIG. 12 (4) is a waveform of the antenna X (or the antenna X ') and the antenna Y (or This is a waveform when the antenna Y ′) emits radio waves of opposite phase.

FIGS. 11 (1) and 11 (2) show a case where two antennas installed near the ceiling radiate radio waves in opposite directions, and radio waves of the same phase are transmitted to antenna X (or antenna). X ′) and antenna Y (or antenna Y ′) are radiated. Figure 11 (1)
In this case, the omnidirectional antennas X and Y are installed in the front half and the rear half of the vehicle, respectively, as radio wave radiation areas. In FIG. 11 (2), omnidirectional antennas X'and Y'are installed in the front half and the rear half of the vehicle as radio wave radiation areas, respectively, and are installed near each end of the front and rear of the vehicle. It is in a state. In such a state, for example, when a radio wave is radiated only from the antenna X (or the antenna X ′), a radio wave having an arbitrary carrier frequency is emitted from the left side of the vehicle as shown in FIG. 12 (1). Then, the vehicle reaches the right side of the vehicle while being attenuated in inverse proportion to the distance from the antenna. On the other hand, when the radio wave is radiated only from the antenna Y (or the antenna Y ′), as shown in FIG. 12 (2), the radio wave of an arbitrary carrier frequency is emitted from the right side of the vehicle and is inversely proportional to the distance from the antenna. Then, the vehicle reaches the left side of the vehicle while decaying.

Then, when both the left and right antennas, that is, the antenna X (or the antenna X ') and the antenna Y (or the antenna Y') radiate radio waves, the antenna is located at an intermediate position (an intermediate position between X and Y). ) In FIG.
As shown in (3), the radio waves are combined and cancel each other. This is because the radio waves of the same phase are combined and cancel each other, so that the electric field disappears and an area where wireless communication is disabled is created. On the other hand, antennas X and Y
As shown in FIG. 12 (4), the radio waves having opposite phases (X 'and Y') are combined to enable communication. Here, a problem is that an area where communication is disabled occurs as shown in FIG. 12 (3). In addition, FIG.
In the case where the phases are not the highly accurate opposite phases as shown in (4), the direct radio waves from the respective antennas are combined and the waveform is distorted.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an antenna device and a radio communication system in which the delay wave of the radio wave radiated from the antenna in the closed space inside the vehicle is small. It is to be. This allows
Without using expensive components such as radio wave absorbers, adaptive transmission / reception antennas, receivers that perform adaptive decoding operations,
An antenna device and a wireless communication system that improve the communication environment in a closed space can be provided. Another object of the present invention is that when a plurality of antennas are installed in the vehicle, an area where communication becomes impossible due to interference between the antennas occurs, or the radiated radio waves of each antenna are combined, It is an object of the present invention to provide a wireless communication system that solves the problem of waveform distortion.

[0010]

DISCLOSURE OF THE INVENTION The present invention discloses a train car in which a plurality of antennas are installed at a position higher than the window frame, and the directivity of radio waves of each antenna faces the window.

Further, according to the present invention, a plurality of antennas are installed in one vehicle, and the installation position of each antenna is set higher than the window frame of the vehicle so that the directivity of radio waves of each antenna faces the window. Disclosed is an in-vehicle antenna device. Further, according to the present invention, a plurality of antennas are installed in one vehicle, and the installation position of each antenna is set higher than the window frame of the vehicle so that the directivity of radio waves of each antenna faces the window and the longitudinal direction of the vehicle. Disclosed is an in-vehicle antenna device that is oriented in a direction other than an angle perpendicular to the direction axis.

The present invention further discloses an in-vehicle antenna device in which a plurality of antennas are arranged along the longitudinal axis of the vehicle. Further, the present invention discloses an in-vehicle antenna device in which directivity of each antenna does not interfere with each other. Further, the present invention discloses an in-vehicle antenna device in which the directivity of each antenna is such that the central portions of adjacent antennas do not overlap each other.

Further, the present invention discloses an in-vehicle antenna device, wherein the plurality of antennas are leaky antennas in which cable-shaped electric wires or waveguides are provided with radiating portions at regular intervals. Further, the present invention discloses an in-vehicle antenna device, wherein each of the plurality of antennas is incorporated into and integrally formed with an advertising board installed in the vehicle.

Further, the present invention discloses an in-vehicle antenna device in which the directivity of each antenna includes the wireless space of a wireless terminal provided in a passenger seat. Furthermore, the present invention is an in-vehicle wireless communication device comprising a plurality of antennas and a wireless terminal provided in a passenger seat, and performing wireless communication between the wireless terminal and each antenna, wherein the plurality of antennas are any one of the above. An in-vehicle wireless device having one antenna device is disclosed.

Further, according to the present invention, a server vehicle and a plurality of dependent vehicles are connected, data is distributed from the server vehicle to the plurality of dependent vehicles, and the dependent vehicle receives the data and collects the data. This is a train radio communication system that collectively transmits data to a server vehicle, and the server vehicle can communicate with a distantly installed center or base. The server vehicle and subordinate vehicles have a plurality of antennas inside, Multiple antennas shall be used for in-vehicle wireless communication,
Further, a train radio communication system in which the plurality of antennas are any one of the above antenna devices is disclosed.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. 1A and 1B show a first embodiment in which an antenna is installed in a vehicle according to an embodiment of the present invention. FIG. 1A is a longitudinal sectional view of the vehicle, and FIG. 1B is a top view of the vehicle. . With respect to a vehicle, its longitudinal direction is defined as a longitudinal axis, and the direction perpendicular thereto is defined as a lateral direction axis and a longitudinal axis. FIG. 1 shows a railway vehicle 1 such as a bullet train, in which a vehicle housing 4 which is a passenger compartment 3 is arranged above a wheel portion 2, and a plurality of windows 5 are attached to a side surface of the vehicle. Figure 1 (1)
In the above, the directional antenna 6 is provided at a position higher than the window frame inside the vehicle. The directional antenna 6 is shown in FIG.
As shown in, the directional antenna group 7 is formed so as to be aligned in the longitudinal direction of the vehicle. The antenna 6 is oriented so that it does not intersect the vertical axis and faces the direction of the window frame 5 (θ ₁ ), and that it does not intersect the longitudinal axis and the lateral axis and the direction of the window frame 5 (θ ₁ ). ₂ ) It has that directivity so that it faces. By providing such directivity, multiple reflected waves and delayed waves in the vehicle can be reduced and the wireless environment can be improved.

The reason for this will be described. Usually, a vehicle housing has a metal part such as a ceiling, a floor, left and right side walls, and windows fitted into the left and right side walls. The window reflects less radio waves than other metal parts, and since the antenna radiation is directed toward the window, the radio waves once emitted outside the window are less likely to return, and as shown in FIG. 1 (2). By setting a plurality of directional antennas as an antenna group and setting the directivity of each antenna near the window, the electric field in the vehicle can be kept substantially uniform. Further, as shown in FIG. 1 (1), directivity is given to the lower side, and as shown in FIG. 1 (2), the horizontal axis and the longitudinal axis are not intersected with each other and are in the window direction. , The reflected waves are drastically reduced.

Further, as shown in FIG. 1, one antenna 6
Has directivity I and II in two C-shaped directions toward the windows on both sides. As a result, one antenna secures the entire pair of left and right seats 8 and 9 as a wireless area.

Further, as shown in FIG. 1 (2), an antenna group 7 in which the antennas 6 are aligned is formed so that a plurality of rows of passenger seats in the vehicle can be secured as a wireless area. As a result, it was possible to provide a stable and reliable wireless environment in each passenger row. The passenger seats were placed in a wireless environment because wireless terminals were installed in the passenger seats, and information about trains (time, location, and other various service information) was provided via this wireless communication terminal, and vehicle sales were carried out. This is because it is possible to issue a request such as a call to a member, and / or to enable a mobile terminal of a passenger sitting in a passenger seat to communicate via this antenna.

Further, as shown in FIG. 1 (2), they are adjacent to each other.
Near the center of the direction of radio waves C₁, C _TwoAnd do not overlap
The antenna is arranged like this. Partially overlap each other
However, since they do not overlap near the center, they are different from each other.
I was able to create a wireless environment close to. Of course the antenna
Completely independent without any overlap due to layout or structure
A wireless environment without significant interference is also possible.

FIG. 2 shows an explanatory view of the antenna 6 inside the vehicle and its radio wave radiation according to the first embodiment of the present invention.
(1) is a longitudinal sectional view of the vehicle, FIG. 2 (2) is a top view of the vehicle, and FIG.
(3) is a schematic diagram of waveforms of multiple delayed waves in which radiation from the antenna 6 is reflected on both side surfaces of the vehicle, and FIG. 2 (4) is schematic diagram of waveforms of multiple delayed waves in which radiation from the antenna 6 is reflected to front and rear surfaces of the vehicle. ,. Θ ₁ and θ shown in FIG. 2 (1) and FIG. 2 (2)
_{When a} radio wave is emitted with an angle of ₂ and the radiation direction is in the vicinity of the center of the window, the radio wave is more transmitted through the window and the reflected wave is less, that is, it is similar to radiation to an open space. FIG. 2 (3) shows a schematic diagram of the radiated radio wave and the multiple delay wave with the received power on the vertical axis and the time on the horizontal axis. For example, the distance between the ceiling and the floor, the distance between the right wall surface and the left wall surface. Assuming that each is 3 m, the first reflected wave from the antenna radiation will appear after 30 ns, the next reflected wave after 60 ns, and then the next 90 ns, but the radiation of the radio wave has directivity in the window. Therefore, even if there is a reflected wave due to leakage, the received power is considerably smaller than in the conventional case. Further, since the direct radiation of radio waves has a large transmission of the radio waves through the window, the reflected waves themselves are considerably small. FIG. 2 (2) shows a case where the radio wave radiated under the same conditions as described above is reflected in the longitudinal direction (front and rear) of the vehicle in addition to the side surfaces of the vehicle. Assuming that the distance between the front wall surface and the rear wall surface of the vehicle in the longitudinal direction is 25 m, as shown in FIG.
As shown in the waveform schematic diagram of (4), the first reflected wave from the direct radiation from the antenna 6 appears 170 ns later,
The next reflected wave appears at 340 ns, then 510 ns later, etc., but since the antenna 6 has directivity (even if there is leakage radiation out of directivity), The received electric field is small.

FIG. 3 is an explanatory view of antenna radiation between an antenna inside a vehicle and an outer wall surface according to an embodiment of the present invention. FIG. 3 (1) is a sectional view of the vehicle and FIG. 3 (2) is It is a vehicle top view. In FIG. 3, the influence of the reflected wave from the external wall surface 10 such as a tunnel or a soundproof wall when the vehicle according to the first embodiment described above is moving on a track will be described.
The angles θ ₁ and θ ₂ by the directional antenna 6 are shown in FIG.
As shown in (2), the radio wave emitted from the antenna 6 goes out through the window, and the radio waves reflected by the tunnel wall and the soundproof wall 10 form the angles θ ₁ and θ ₂ similarly to the radiation angle. The probability of waves re-entering the vehicle is reduced. In addition, it has a large damping effect because it contacts a large area with stones sown on the ground or railroad tracks. Further, in a bullet train or the like in which a seat table is arranged in a vehicle, the angle of θ ₂ is more likely to reach a mobile wireless terminal operated by a crew member or a passenger in the vehicle.

FIG. 4 shows a second embodiment in which two antennas 6A and 6B are arranged side by side in the vehicle according to the embodiment of the present invention. FIG. 4 (1) is a sectional view of the vehicle and FIG. 2) is a vehicle top view. 7A and 7B are antenna groups.
In the second embodiment, the first embodiment described above communicates with one type of antenna and one type of frequency, whereas two systems of unidirectional antennas 6A and 6B are used, and further, separate frequencies are used. It enables communication. The directional antenna 6A and the directional antenna 6B are directed in the direction of crossing each other and toward the window 5 distant (opposite position) from each other. By disposing a plurality of antenna groups on the ceiling, a uniform electric field can be maintained in the vehicle. As a result, it is possible to have a communication environment having the same communication environment as that of the first embodiment and a communication capacity of double the communication capacity.

FIG. 5 is an explanatory view of a radio wave radiation state in a state where two moving trains 1A and 1B according to the embodiment of the present invention are close to each other. In FIG. 5, when the vehicle according to the second embodiment described above is moving on a track, it is assumed that an up train and a down train pass each other. Becomes When the vehicles pass each other, the positions where the radio waves overlap with each other are the radio wave a and the radio wave b in the vehicle in the accident, and there is almost no influence of the radio wave on the other vehicle. This is because the inside of the closest window # 1 uses the radio waves a and b for both up and down, and communication can be continued without interference.

FIG. 8 shows a schematic view of the inside of the vehicle according to the embodiment of the present invention. FIG. 8 (1) is a side sectional view of the vehicle seen from the lateral direction, and FIG. 8 (2) is seen from the inside of the vehicle. FIG. FIG. 8 (1) shows the case where the leaky antenna 6C is used as the antenna. FIG. 8 (2) is a view seen from the rear of the vehicle. As shown in FIG. 8 (2), actually, different leaky antennas 6C ₁ and 6C ₂ are arranged at the edges of the luggage rack. The leakage antennas 6C ₁ and 6C ₂ have two ways of radio wave emission directions, that is, directivity. The first is to maintain θ ₁ and θ ₂ as described with reference to FIG. 1, and to be directed toward the opposite seat and window as shown in FIG. The opposite side means that the antenna 6C is the seat 9 and its window direction, and the antenna 6C is
C ₂ refers to the seat 8 and its window direction. Second, the antenna 6C ₁ is directed toward the seat 8 of the user,
C ₂ is oriented so that it faces the user's seat 9. The former is preferable, but the latter is also possible.

FIG. 6 shows the case of a two-story vehicle according to the embodiment of the present invention. Communication on the second floor of the vehicle is carried out by radio wave a using an eight-shaped directional antenna 6C, and communication on the first floor is carried out by radio wave c using the same eight-shaped directional antenna 6D. I do. The radio waves a and c have different frequencies. When different frequencies are used in this way, even if radio waves on the second floor enter from an external soundproof wall or the like, there is no interference because the first floor communicates with radio waves c having different frequencies.

FIG. 7 shows the case of a two-story vehicle according to another embodiment of the present invention. Communication on the second floor of the vehicle 1 is performed by the unidirectional antennas 6A and 6B and the unidirectional antenna 6 on the first floor.
I decided to do it on E and 6F. The relationship between the antenna and the frequency is the directional antenna 6C of the directional antenna and the frequency f.
1, the directional antenna 6D and the frequency f2, and the first floor is the directional antenna 6E and the frequency f3, and the directional antenna 6F and the frequency f4. The antennas 6A and 6B on the second floor are directed in a direction away from each other in a direction crossing each other. Also, by arranging multiple antenna groups on the ceiling, it is possible to maintain a uniform electric field in the cabin. The same applies to the first floor. Here, it is assumed that the external soundproof wall 10
Even when the radio wave (reflected wave) on the second floor enters the first floor due to the above reasons, the frequencies f1 and f2 on the second floor differ between the frequency f3 and the frequency f4 on the first floor, and therefore no interference occurs.

According to the above-mentioned respective embodiments, even in a completely enclosed space made of metal or the like, by providing an open space on a certain surface, when radio waves are radiated toward the open space, there is no reflection from that part. Using that principle, the antenna in the upper part of the vehicle (near the ceiling) radiates to the window at an angle of θ ₁ from the vertical direction of the vehicle, and radiates to the window at an angle of θ _{2 to} the longitudinal direction of the vehicle, thereby producing a multi-delay wave. Can be reduced, and a good wireless communication space can be obtained.

Further, windows are usually installed on both side wall surfaces of a vehicle, and the window portion reflects less radio waves than the metal portion which is the vehicle housing. Therefore, by setting the antenna installed near the ceiling to have directivity in the direction of the center of the window, it is possible to reduce the reflection of radio waves radiated from the antenna, and thus reduce the generation of delayed waves. You can

Next, radio waves when a plurality of antennas are installed in the vehicle will be described. FIG. 13 shows a cross-sectional view of the vehicle side when the antenna is installed in the vehicle according to the embodiment of the present invention, and FIG. 13 (1) shows the omnidirectional antenna 6
FIG. 13 (2) is a side sectional view of a vehicle in which a directional antenna 6H is installed for radio waves with G, and FIG. 13 (2) is a side sectional view of a vehicle in which two unidirectional directional antennas 6J and 6M are installed. The antenna 6G provides all directions, and the antenna 6H provides the unidirectional direction as a radio space. Each of the antennas 6J and 6M provides its unidirectional direction as a wireless space. Also,
FIG. 14 is a waveform diagram showing the relationship between the attenuation of radio waves radiated from the antenna in the vehicle according to the present invention and the distance in the vehicle. FIG. 14 (1) shows the antenna 6G (or the antenna 6G).
J) only waveform, Fig. 14 (2) shows antenna 6H
(Or antenna 6M) only waveform, FIG.
(3) is a waveform when the antenna 6G (or the antenna 6J) and the antenna 6H (or the antenna 6M) emit radio waves.

In FIG. 13A, the antenna 6G is omnidirectional (or bidirectional antenna), the antenna 6H is a directional antenna, and the radio wave device is not radiated to the antenna 6G side. In addition, in FIG. 13B, the antenna 6J and the antenna 6M are directional antennas,
The figure shows the case where an antenna with a unidirectional or sharper directivity is installed. In this state, for example,
When the radio wave is radiated only from the antenna 6G (or the antenna 6J), as shown in FIG. 14 (1), when the radio wave of an arbitrary carrier frequency is emitted from the left side of the vehicle, it is inversely proportional to the distance from the antenna. Attenuates to the right side of the vehicle while decaying. On the other hand, when the radio wave is radiated only from the antenna 6H (or the antenna 6M), as shown in FIG. 14 (2), the radio wave having an arbitrary carrier frequency is emitted from the center side of the vehicle and is inversely proportional to the distance from the antenna. Then, the vehicle reaches the right side of the vehicle while decaying.

Here, a case where both the left and right antennas, that is, the antenna 6G (or the antenna 6J) and the antenna 6H (or the antenna 6M) radiate radio waves will be described. The radio wave radiated from the antenna 6G (or 6J) weakens as the distance increases, and since the radio wave from the antenna 6H (or 6M) is strongly radiated, the radio wave from the antenna 6G (or 6J) is erased and the antenna 6H (or 6M) becomes dominant. That is, on the side of the antenna 6H (or 6M), it is possible to forcibly eliminate the interference due to the antenna 6G (or 6J). This means that if the antennas are installed so that the radiation from the antennas does not face each other, they do not interfere with each other.

FIG. 15 is an upper sectional view of the inside of the vehicle in which the directional antenna according to the embodiment of the present invention is installed.
(1) is a vehicle equipped with a unidirectional antenna.
In FIGS. 15 (1) and 15 (2), first, the unidirectional antenna 6N (or the planar directional antenna 6R) is arranged in each part of the vehicle. The directivity center line forms an arbitrary angle θ ₃ with respect to the vehicle and radiates radio waves. The radio wave emitted from the antenna 6N (or 6R) travels in all directions in the directional plane, but the radio wave also weakens as the distance from the antenna increases. Radio waves emitted in the direction of the directional center line are reflected on the vehicle wall surface. The reflected radio wave also has an angle of θ ₂ and is reflected, but the unidirectional antenna 6Q (or the planar directional antenna 6T) is arranged in the area of the reflected wave, and the fundamental radio wave that is sufficiently strong against the reflected wave is radiated. , Antenna 6R (or 6
The influence (interference) of N) can be almost ignored. Similarly, the radio wave radiated from the antenna 6Q (or 6T) is also reflected on the vehicle wall surface, but the unidirectional antenna 6P is provided in that area.
(Or the planar directional antenna 6S) is arranged, the antenna 6Q (or 6T) and the antenna 6N are similarly provided.
(Or 6R) effect (interference) can be almost ignored.
In this way, by installing the directivity directions of the respective antennas in the vehicle so as to form an arbitrary angle, the influence of the other antennas can be reduced and the entire vehicle can be used as a radio wave area. .

FIG. 16 shows a concrete example of installing the directional antenna according to the embodiment of the present invention. FIG. 16 (1) is a schematic view of a planar array antenna 6U, and FIG. 16 (2) is normally installed in a vehicle. FIG. 16C is a schematic view of the advertising board 11 to be produced, and FIG. FIG. 16A is a schematic diagram of a plane array antenna 6U having a feeding point 6a regularly as a directional antenna, and this plane array antenna 6U.
16 (2) is incorporated into the advertisement board 11 generally installed in the vehicle, that is, inside the advertisement 12, as shown in FIG.
6 (3), the antenna 6U
Since it is not directly visible inside the vehicle, it does not spoil the aesthetics. Further, since the advertising board is often installed near the ceiling of the vehicle or on the upper side wall or the like, it is convenient to install the antenna as shown in FIG. 16 (3).

FIG. 9 shows a system configuration diagram when the vehicles according to the embodiment of the present invention are connected. Server vehicle 2
0 and a plurality of dependent vehicles 21 (# 1 to #
n). In addition, a wireless base station 22 that is wirelessly communicated via the external communication antenna 22 of the server vehicle is installed outside the station or near the railroad track.
Is connected to the comprehensive information center 24. The comprehensive information center 24 is connected to various lines such as an internet line, a public line, and a dedicated line to send and receive necessary information. The server vehicle 20 includes an external communication antenna 22, an external communication device 25, an in-vehicle communication device 26, and an in-vehicle antenna 2.
7, an inter-vehicle communication device 28, and a server 29 (control device) that controls these various devices are mounted. Next, the subordinate vehicles (# 1 to #n) 21 are equipped with an inter-vehicle communication device with a front vehicle, an in-vehicle communication device, an in-vehicle antenna, and an inter-vehicle communication device with a rear vehicle. Also, two inter-vehicle communication devices are installed in order to communicate with the front and rear vehicles. A wireless terminal 35 is installed in each of the passenger seats 34 of the server vehicle 20 and the subordinate vehicle 21 to enable wireless communication with the in-vehicle antenna 27. The in-vehicle antenna 27 corresponds to the antenna shown in FIGS.
In addition to this, free terminals include a conductor terminal 36, a salesperson terminal 37, a portable wireless terminal 39 owned by a passenger, and the like, and wireless communication is possible through an in-house antenna 37.

In this wireless communication system, the data received from the external wireless base station can be sequentially delivered to the server vehicle 20 and the subordinate vehicles 21 (# 1 to #n) via the external communication antenna, and , The data received from the inside of each vehicle via the in-vehicle antenna 27 is used as the subordinate vehicles #n to #.
1, the server vehicle 20, and the data are collected while being collected one after another, and the wireless base station 23 is collected via the external communication antenna 22.
Can be sent to. This is a multi-valued modulation wireless line in which RF frequencies or IF frequencies are arranged in order and transmitted to a vehicle with a server and finally returned to bit data there for processing. Enables wireless communication between various wireless terminal devices such as seat terminals placed in seats in the vehicle, terminals for conductors, terminals for in-vehicle salespersons, portable wireless terminals brought into the vehicle, and the outside of the vehicle. Can be Here, the server (control device) of the server vehicle transmits and receives the multiplexed carrier waves,
Frequency allocation work such as data transmission to destinations to various wireless terminals in the vehicle and collectively transmitting data collected from various wireless terminals from the vehicle as a state with the destination of the data, The work is to multiplex a plurality of transmission data in the same frequency band. In the subordinate vehicle, the data is wirelessly transmitted to each vehicle according to the frequency assigned from this server, the data is passed to the next vehicle, or the data received from the wireless terminal in each vehicle is collected and the server vehicle side Pass data to dependent vehicles of
That is the work to be done.

[0037]

According to the present invention, it is possible to provide an antenna and a wireless communication system in which the delay wave of the radio wave radiated from the antenna in the closed space is small and to provide the radio wave absorber and the adaptive radio wave. It is possible to provide an antenna installation and a wireless communication system that improve a communication environment in a closed space without using expensive transmitting and receiving antennas, expensive components such as a receiver that performs an adaptive decoding operation. Another effect of the present invention is that when a plurality of antennas are installed in the vehicle, an area where communication becomes impossible due to interference between the antennas occurs, or the radiated radio waves of each antenna are combined, It is possible to provide a wireless communication system that solves the distortion of the waveform.

[Brief description of drawings]

FIG. 1 shows a first example in which an antenna is installed in a vehicle according to an embodiment of the present invention, (1) is a vehicle sectional view,
(2) is a vehicle top view.

FIG. 2 is an explanatory view of an antenna inside a vehicle and its radio wave radiation according to a first embodiment of the present invention, (1) is a sectional view of the vehicle, (2) is a top view of the vehicle, and (3) is a view from the antenna. Waveform schematic diagram of multiple delayed waves whose radiation reflects on both sides of the vehicle,
(4) is a schematic diagram of a waveform of a multiple delay wave in which radiation from an antenna is reflected on the front and rear surfaces of a vehicle.

FIG. 3 is an explanatory view of antenna radiation between an antenna inside a vehicle and an outer wall surface according to the embodiment of the present invention,
(1) is a vehicle cross-sectional view and (2) is a vehicle top view.

FIG. 4 shows a second example in which an antenna is installed in the vehicle according to the embodiment of the present invention, (1) is a vehicle sectional view,
(2) is a vehicle top view.

FIG. 5 is an explanatory diagram of a radio wave radiation state in a state where moving vehicles are close to each other according to the embodiment of the present invention.

FIG. 6 shows a first explanatory diagram in the case of a two-story vehicle according to an embodiment of the present invention.

FIG. 7 shows a second explanatory diagram in the case of a two-story vehicle according to the embodiment of the present invention.

FIG. 8 is a schematic view of the inside of the vehicle according to the embodiment of the present invention, (1) is a side sectional view of the vehicle as seen from the lateral direction, and (2).
FIG. 3 is a perspective view seen from the inside of the vehicle.

FIG. 9 shows a system configuration diagram when the vehicles according to the embodiment of the present invention are connected.

10A and 10B are explanatory views of a conventional antenna inside a vehicle and its radio wave radiation, wherein (1) is a sectional view of the vehicle, (2) is a top view of the vehicle, and (3) is radiation from the antenna on both side surfaces of the vehicle. FIG. 4 is a schematic diagram of a waveform of a reflected multiple delayed wave, and (4) is a schematic diagram of a waveform of the multiple delayed wave in which radiation from an antenna is reflected on the front and rear surfaces of a vehicle.

FIG. 11 is a side sectional view of a vehicle when an antenna is installed in a conventional vehicle, (1) is a side sectional view of a vehicle having an omnidirectional antenna, and (2) is a vehicle having a directional antenna. FIG.

FIG. 12 is a waveform diagram showing the relationship between the attenuation of radio waves radiated from an antenna in a conventional vehicle and the distance in the vehicle,
(1) is the waveform when only the antenna X is used, (2) is the waveform when only the antenna Y is used, (3) is the waveform when the antenna X and the antenna Y emit radio waves in phase, and (4) is the antenna X 3 is a waveform when the antenna Y emits radio waves of opposite phase.

FIG. 13 is a side sectional view of the vehicle when an antenna is installed in the vehicle according to the embodiment of the present invention, (1) is a side sectional view of the vehicle in which the omnidirectional antenna and the directional antenna are installed,
(2) is a side sectional view of a vehicle in which two directional antennas are installed.

FIG. 14 is a waveform diagram showing the relationship between the attenuation of radio waves radiated from the antenna in the vehicle according to the present invention and the distance in the vehicle, where (1) is the waveform when only the antenna A is used, and (2) is the antenna. The waveform in the case of only B, (3) is the waveform when the antenna A and the antenna B emit radio waves.

FIG. 15 is an upper cross-sectional view of the inside of a vehicle in which a directional antenna according to an embodiment of the present invention is installed, (1) is a vehicle in which a unidirectional antenna is installed, and (2) is a unidirectional antenna. Is a vehicle that has been installed.

FIG. 16 shows a specific example of installing a directional antenna according to an embodiment of the present invention, (1) is a schematic view of a planar array antenna, and (2) is a schematic view of an advertising board normally installed in a vehicle. , (3) is a schematic view in which a plane array antenna is incorporated in an advertising board.

[Explanation of symbols]

1 vehicle 5 windows 6 Directional antenna

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazumasa Nakamura             3-14-20 Higashi-Nakano, Nakano-ku, Tokyo Stocks             Hitachi Kokusai Electric Co., Ltd. (72) Inventor Mitsuhiro Okada             3-14-20 Higashi-Nakano, Nakano-ku, Tokyo Stocks             Hitachi Kokusai Electric Co., Ltd. (72) Inventor Akihiro Shinkawa             1-1, Sanbonmatsucho, Atsuta-ku, Nagoya-shi, Aichi             Within Japan Vehicle Manufacturing Co., Ltd. F-term (reference) 5J046 AA04 AB08 MA08                 5J047 AA04 AB08 EA01                 5K067 AA23 BB05 BB21 EE02 EE10                       EE25 EE43 GG01 GG11 KK02                       KK03

Claims (11)

[Claims] 1. A train car in which a plurality of antennas are installed at a position higher than a window frame, and the directivity of radio waves of each antenna faces the window. 2. A vehicle in which a plurality of antennas are installed in one vehicle, and the installation position of each antenna is set higher than the window frame of the vehicle so that the directivity of radio waves of each antenna faces the window. Internal antenna device. 3. A plurality of antennas are installed in one vehicle, and the installation position of each antenna is set higher than the window frame of the vehicle, and the directivity of radio waves of each antenna faces the window and the longitudinal direction of the vehicle. An in-vehicle antenna device that is oriented in a direction other than an angle perpendicular to the direction axis. 4. The in-vehicle antenna device according to claim 2, wherein the plurality of antennas are arranged in line along a longitudinal axis of the vehicle. 5. The in-vehicle antenna device according to claim 2, wherein the directivities of the antennas do not interfere with each other. 6. The in-vehicle antenna device according to any one of claims 2 to 4, wherein directivity of each antenna is such that adjacent antennas do not overlap each other at their center portions. 7. The vehicle according to claim 2, wherein each of the plurality of antennas is a cable-shaped electric wire or a leaky antenna in which a waveguide is provided with radiating portions at regular intervals. Internal antenna device. 8. The in-vehicle antenna device according to any one of claims 2 to 7, wherein each of the plurality of antennas is integrally formed by being incorporated in an advertising board installed in a vehicle. 9. The in-vehicle antenna device according to claim 2, wherein the directivity of each antenna includes a wireless space of a wireless terminal provided in a passenger seat. 10. An in-vehicle wireless communication device, comprising: a plurality of antennas; and a wireless terminal provided in a passenger seat, wherein wireless communication is performed between the wireless terminal and each antenna. An in-vehicle wireless device having any one of the antenna devices as set forth above. 11. A server vehicle and a plurality of dependent vehicles are connected to each other, data is distributed from the server vehicle to the plurality of dependent vehicles, and the dependent vehicle receives the data and collects the collected data. Is a train wireless communication system capable of communicating with a distantly installed center or a wireless base. The server vehicle and the subordinate vehicle have a plurality of antennas inside, The antenna shall be used for in-vehicle wireless communication.
A train radio communication system in which the plurality of antennas are antenna devices according to any one of claims 2 to 10.