JP2002208044A - Private narrow band communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that information can not be normally given or received in a normal communication area and the problem that an on-vehicle equipment reacts in an adjacent traffic lane since the on-vehicle reacts before the communication area due to the increase of an electric field intensity level resulted from a surrounding radio environment such as a tool gate roof in a conventional private narrow band communication system. SOLUTION: The position of an on-vehicle equipment is measured by using a radio wave incoming direction measuring equipment, and when the on-vehicle is present in a communication area, a communication line is established between a passage side antenna and the on-vehicle equipment. Thus, it can prevent an erroneous operation of the on-vehicle equipment due to the increase of an electric field intensity level outside the communication area resulted from a surrounding radio environment so that normal communication is assured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dedicated narrow-area communication system (Dedicated communication system) that performs reliable communication in a limited area.
Short Range Communication (DSRC).

[0002]

2. Description of the Related Art FIG. 6 shows a non-stop automatic system for collecting tolls on a toll road from a passing vehicle by performing wireless communication between a roadside device provided on the road and an on-board unit mounted on the passing vehicle. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external view showing an example of a conventional dedicated narrow-area communication system typified by a toll collection (hereinafter, referred to as ETC) system. This is an example described in Japanese Patent Application Laid-Open No. Hei 10-11625.

In FIG. 6, reference numerals 1a and 1b denote lanes, and 2a to 2a.
2c is a lane separation zone, 3a is the traveling direction of the lane 1a,
Is a vehicle entering the tollgate area of the lane 1a, 5 is a vehicle-mounted device mounted on the vehicle 4, 6a and 6b are arranged at predetermined intervals in the traveling direction 3a of the vehicle 4, and cross the lane 1a. , The gate-shaped supports 7c and 7d are roadside antennas mounted on the supports 6a and 6b, respectively, and 8a and 8b are the roadside antennas 7a and 8b, respectively.
Beams 9c and 9d radiated toward the lower lane 1a from c and 7d are the roadside antennas 7c and 7d, respectively.
Communication areas 10a and 10b correspond to the communication areas 9 respectively.
c, gray zones around 9d, 17c and 17
d, 17e and 17f are vehicle detection sensors provided in pairs on the lane divider 2a, respectively, and defining the communication areas 9c and 9d.

Next, the operation will be described. When the vehicle 4 reaches the communication area 9c and the front end of the vehicle 4 is detected by the vehicle detection sensor 17c, the roadside antenna 7c starts communication with the vehicle-mounted device 5 for toll collection, and then detects the vehicle at the subsequent stage. When the tip of the vehicle 4 is detected by the sensor 17d, the communication is stopped. That is, if the traveling vehicle 4 is an ETC vehicle equipped with the vehicle-mounted device 5, the roadside antenna 7c
Information necessary for performing toll collection between the toll booth and the ETC vehicle in a non-stop state is transmitted and received via. Thereafter, when the vehicle 4 advances and reaches the next communication area 9d, information is exchanged between the tollgate and the vehicle 4 via the roadside antenna 7d. The information exchanged between the two communication areas 9c and 9d is different. For example, in the first communication area 9c, the exchange of information is different, such as confirmation of the vehicle type, and in the subsequent communication area 9d, the deduction of a fee. Is performed.

Here, in FIG. 6, communication areas 9c and 9d
The highlight of the white part is the roadside antenna 7
The area irradiated by the beams 8a and 8b of c and 7d may not communicate around the communication areas 9c and 9d depending on the condition of the vehicle-mounted device 5 (reception sensitivity, etc.) and the surrounding radio wave environment such as a tollgate roof. Gray zones of certainty 10a, 10b
This is because there is. Therefore, the tip of the vehicle 4 is detected by the vehicle detection sensors 17c to 17f so that the information is transmitted and received in the communication areas 9c and 9d where the information can be transmitted and received most accurately. The start and end of the communication are controlled between.

[0006]

Since the conventional dedicated narrow-area communication system is configured as described above, the on-vehicle device is placed in front of the communication area due to an increase in the electric field intensity level due to the surrounding radio wave environment such as a tollgate roof. In other words, there is a problem that normal information cannot be transmitted / received in a regular communication area, and a problem that an onboard device reacts in an adjacent lane. Further, in order to avoid the increase in the electric field intensity level, a radio wave absorber must be provided on the surrounding reflecting structure, and there is a problem that a huge cost is required to reduce the reflected wave. Furthermore, in order to avoid this problem, even if an attempt is made to start communication with the on-vehicle device after the on-vehicle device is sufficiently pulled into the communication area by applying a time delay to the detection signal of the vehicle detection sensor, depending on the vehicle type, Because the positional relationship (distance) between the front end of the vehicle and the vehicle-mounted device may be different, or the vehicle may run at a low speed (or congestion), the vehicle-mounted device may still exist in the gray zone with uncertainty. Therefore, there is a problem that reliable communication cannot be established depending on the situation.

[0007] The present invention has been made to solve the above-described problems, and normal communication can be reliably performed regardless of the surrounding radio wave environment (no need to take measures to reduce reflected waves). The purpose is to realize a dedicated narrow-area communication system. It is another object of the present invention to provide a dedicated narrow-area communication system capable of reliably performing communication only within a desired communication area regardless of the installation position of the vehicle-mounted device depending on the vehicle type.

[0008]

A dedicated narrow-area communication system according to a first aspect of the present invention includes an arrival direction measuring device for specifying a position of an on-vehicle device based on a transmission signal from an on-vehicle device mounted on a passing vehicle; A roadside antenna for establishing a communication line with the on-vehicle device only when the position of the on-vehicle device specified by the arrival direction measuring device is within a predetermined communication area.

[0009] Also, in the dedicated narrow-area communication system according to the second invention, in the first invention, the arrival direction measuring device is:
The position of the vehicle-mounted device is detected based on a signal requesting the establishment of a communication link transmitted from the vehicle-mounted device, and the roadside antenna has a position measured by the arrival direction measuring device,
A signal for permitting connection of a communication line is transmitted to an on-vehicle device in a predetermined communication area of the roadside antenna.

Further, the dedicated narrow-area communication system according to a third aspect of the present invention is the exclusive-use narrow-area communication system according to the first aspect, further comprising, after receiving the interrogation signal from the roadside antenna, transmitting a signal requesting the roadside antenna to establish a communication link. It is equipped with a vehicle-mounted device for sending.

In a fourth aspect of the present invention, in the dedicated short-range communication system according to the third aspect, the on-vehicle device includes identification information for identifying the on-vehicle device in a signal requesting the establishment of a communication link. It had.

In a fifth aspect of the present invention, there is provided the dedicated narrow-area communication system according to the first aspect, wherein the arrival direction measuring device comprises:
Corresponding to the identification information for identifying the vehicle-mounted device in the signal requesting the establishment of the communication link from the vehicle-mounted device,
A position of the vehicle-mounted device in a predetermined communication area in the roadside antenna is specified, and the roadside antenna has a communication line connection signal having identification information corresponding to the vehicle-mounted device located in the predetermined communication area. Is transmitted.

[0013] In the exclusive short-range communication system according to a sixth aspect of the present invention, in the first aspect, the vehicle-mounted device emits a signal from the vehicle-mounted device to the roadside antenna after establishing a communication line with the roadside antenna. Information signal is received by the radio wave arrival direction measuring device to detect the position of the vehicle-mounted device,
Immediately after the vehicle-mounted device has passed through the communication area, a communication line between the vehicle-mounted device and the roadside antenna is disconnected.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a perspective view showing a dedicated narrow-area communication system according to the first embodiment, where (a) shows a case of one lane, and (b) shows a case of two lanes. FIG. 2 is a diagram showing electric field strength level characteristics for understanding the operation, and FIG. 3 is a diagram showing a communication transaction of the dedicated narrow area communication system according to the first embodiment.

In FIG. 1 and FIG. 2, reference numeral 11 denotes a communication link registration signal for requesting the establishment of a communication link, which is transmitted from the vehicle-mounted device to the roadside antenna. A radio wave arrival direction measuring device 13 is a reflection structure such as a tollgate roof placed near the roadside antenna 7, and 14 is an information signal emitted from the vehicle-mounted device 5 to the roadside antenna 7. Reference numerals 1 to 10 are exactly the same as the conventional dedicated narrow-area communication system.

In FIG. 3, reference numeral 15 denotes an interrogation signal transmitted by the roadside antenna 7 at all times, and reference numeral 16 denotes a communication transmitted by the roadside antenna 7 to the vehicle-mounted device 5 for permitting connection to a communication line. This is a line connection signal.

Next, a series of operations of the dedicated narrow-area communication system will be described with reference to FIG. Vehicle 4
a enters the lane 1a in the traveling direction 3a.
From the roadside antenna 7, an interrogation signal 15 for giving a response request to the vehicle-mounted device 5 or a request for starting the communication function is always transmitted. When the vehicle 4a approaches the roadside antenna 7 and the electric field intensity level of the interrogation signal 15 emitted from the roadside antenna 7 becomes higher than a certain level, the vehicle-mounted device 5a sends out the communication link registration signal 11 to the roadside antenna 7.
The communication link registration signal 11 includes identification information (on-vehicle device ID) unique to the on-vehicle device set in advance on the on-vehicle device. At this time, the radio wave direction-of-arrival measuring device 12 is mounted on the vehicle-mounted device 5a.
And receives the communication link registration signal 11 issued from the device, and measures the position of the vehicle-mounted device 5a. At the same time, from the received signal of the communication link registration signal 11, the vehicle-mounted device ID corresponding to the vehicle-mounted device 5a whose position is specified is identified. Here, the roadside antenna 7 determines whether or not the measured position of the vehicle-mounted device 5a exists in the communication area 9 based on the position information measured by the radio wave arrival direction measuring device 12, and If it exists in the communication device 9, the communication line connection signal 16 is transmitted to the vehicle-mounted device 5a. The communication line connection signal 16 includes information on the vehicle-mounted device ID identified by the radio wave direction-of-arrival measuring device 12. At this time, the vehicle-mounted device 5a receives the vehicle-mounted device ID information included in the communication line connection signal 16 transmitted from the roadside antenna 7 and the vehicle-mounted device I set in advance in the vehicle-mounted device.
D, and if they match, the communication line connection signal 16
When the timer is activated from the point of receiving, a certain time,
A communication line is established between the roadside antenna 7 and the vehicle-mounted device 5a.
If they do not match, communication between the roadside antenna 7 and the vehicle-mounted device 5a is not performed. That is, the traveling vehicle 4
If a is an ETC vehicle equipped with the vehicle-mounted device 5a, information necessary for non-stop toll collection between the toll booth and the ETC vehicle is transmitted and received via the roadside antenna 7. If the position of the vehicle-mounted device 5a is outside the communication area 9,
The roadside antenna 7 sends a communication line connection signal 1 to the vehicle-mounted device 5a.
6 is not transmitted, the communication line is not established, and the roadside antenna 7 transmits the interrogation signal 15 again.

Next, as shown in FIG. 1B, the case where the radio wave radiated from the roadside antenna 7 is multiply propagated between the reflecting structure 13 such as a tollgate roof and the road surface will be described. In this case, the gray zone 10 extends not only to the lane 1a, which is the own lane, but also to the lane 1b, which is an adjacent lane. As shown in FIG. The in-vehicle device mounted on the vehicle 4c in the communication area rises above the minimum reception level of the on-vehicle device mounted on the vehicle 4c and operates in an unstable manner. There is no such unstable movement because it passes through.) When the lane 1b is not the ETC lane, the vehicle-mounted device 5b of the vehicle 4b traveling in the lane 1b is determined to be outside the communication area 9 based on the position information of the vehicle-mounted device 5b measured by the radio wave arrival direction measuring device 12. Roadside antenna 7 on the lane 1a
Does not transmit the communication line connection signal 16 to which the on-vehicle device ID information of the on-vehicle device 5b is assigned, and does not erroneously communicate. Also, even if the electric field strength level may be high in the lane 1a before the communication area 9, the vehicle-mounted device 5a is outside the communication area 9, so that the roadside antenna 7
Does not transmit the communication line connection signal 16, and the communication line is not established.

The operation example in the case where one roadside antenna 7 is placed in the lane 1a has been described above, but the same operation is performed even when the second roadside antenna 7 is placed at a certain distance. I do. That is, it is possible to exchange different information such as confirmation of a vehicle type in the first communication area 9 and deduction of a fee in the latter communication area 9. The invention is not limited to this, and a plurality of roadside antennas 7 may be cascaded. Further, in the above description, an example has been described in which the vehicle-mounted device ID stored in the internal memory of the vehicle-mounted device 5 is added to the communication link registration signal 11 when the communication-link registration signal 11 is transmitted. Even if the communication link registration signal 11 is transmitted at the same time, if the transmission position of the communication link registration signal 11 corresponding to each vehicle-mounted device (vehicle device ID) can be identified by the radio wave direction-of-arrival measuring device 12, other configurations are used. It may be. For example, even when the communication link registration signal 11 is transmitted from the vehicle-mounted device 5, even if the code number generated by the random number generator included in the vehicle-mounted device 5 is added to the communication link registration signal 11, the arrival of the radio wave A similar function can be performed by the direction measuring device 12.

According to this embodiment, the position of the vehicle-mounted device is measured using the radio wave direction-of-arrival measuring device. If the vehicle-mounted device is within the communication area, the roadside antenna and the vehicle-mounted device establish a communication line. This prevents erroneous operation of the vehicle-mounted device due to an increase in the electric field strength level outside the communication area due to the surrounding radio wave environment, thereby enabling reliable communication. In addition, in order to suppress the increase in the electric field intensity level outside the communication area, there is no need to specify the radio wave reflector that causes the radio wave absorber or to install a radio wave absorber or a reflector on the reflector. There is an effect that the suppression and the operation of the dedicated narrow-area communication system become easy. In addition, there is no need to consider the distance difference between the front end of the vehicle and the vehicle-mounted device depending on the vehicle type, the time difference between the detection time of the vehicle detection sensor depending on the running state of the vehicle and the time when the vehicle-mounted device actually reaches the communication area. Thus, it is possible to realize a dedicated narrowband communication system capable of exchanging information with the roadside antenna only in a desired communication area. Furthermore, there is an effect that the system performance can be improved without changing the existing vehicle-mounted device and the vehicle.

Embodiment 2 FIG. FIG. 4 is an external view of a dedicated band communication system according to the second embodiment of the present invention, and FIG. 5 is a diagram illustrating a communication transaction of the dedicated narrow area communication system according to the second embodiment.

In the second embodiment, after the vehicle-mounted device 5a establishes a communication line with the roadside antenna 7, the radio wave arrival direction measuring device 12 receives the information signal 14 emitted from the vehicle-mounted device 5a toward the roadside antenna 7. To detect the position of the vehicle-mounted device 5a,
Immediately after the vehicle-mounted device 5a passes through the communication area 9, the communication line between the vehicle-mounted device 5a and the roadside antenna 7 is disconnected. The electric field strength level characteristics for explaining the operation of the dedicated narrow-area communication system according to the second embodiment are the same as those in FIG.

According to this embodiment, the position of the vehicle-mounted device is measured using the radio wave arrival direction measuring device, and the communication line can be disconnected immediately after the vehicle-mounted device has passed the communication area. Therefore, malfunction of the vehicle-mounted device due to an increase in the electric field intensity level outside the communication area due to the gray zone immediately after passing through the communication area or the surrounding radio wave environment is suppressed, and thus there is an effect that reliable communication can be performed.

[0024]

According to the present invention, the position of the vehicle-mounted device is measured using the radio wave direction-of-arrival measuring device, and if the vehicle-mounted device is within the communication area, the roadside antenna and the vehicle-mounted device establish a communication line. This prevents erroneous operation of the vehicle-mounted device due to an increase in the electric field strength level outside the communication area due to the surrounding radio wave environment, thereby enabling reliable communication.

Further, according to the present invention, the position of the vehicle-mounted device is measured using the radio wave arrival direction measuring device, and the communication line can be disconnected immediately after the vehicle-mounted device has passed the communication area. Therefore, it is possible to suppress a malfunction of the vehicle-mounted device due to an increase in the electric field intensity level outside the communication area due to the gray zone immediately after passing through the communication area or the surrounding radio wave environment.

[Brief description of the drawings]

FIG. 1 is a perspective view showing Embodiment 1 of a dedicated narrow-area communication system according to the present invention.

FIG. 2 is an electric field strength level characteristic diagram for explaining the operation.

FIG. 3 is a communication transaction of the dedicated narrow area communication system according to the first embodiment.

FIG. 4 is a perspective view showing Embodiment 2 of the dedicated narrow area communication system according to the present invention.

FIG. 5 is a communication transaction of the dedicated narrow area communication system according to the second embodiment.

FIG. 6 is a perspective view showing a conventional proprietary narrow-area communication system.

[Explanation of symbols]

 Reference Signs List 1 lane 2 lane divider 3 traveling direction 4 vehicle 5 on-vehicle device 6 support 7 roadside antenna 8 beam 9 communication area 10 gray zone 11 communication link registration signal 12 radio arrival direction measuring instrument 13 reflection structure 14 information signal 15 interrogation signal 16 Communication line connection signal 17 Vehicle detection sensor

Continued on the front page. (72) Inventor Masato Sato 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (72) Inventor Shigeho Inane 2-3-2-3 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric F term in reference (reference) 3E027 EA01 5H180 AA01 BB04 CC12 EE10 FF13 5K067 AA02 AA33 EE02 EE44 EE57 JJ53 KK02

Claims (6)

[Claims] An arrival direction measuring device for specifying a position of an on-vehicle device based on a transmission signal from an on-vehicle device mounted on a passing vehicle, and a position of the on-vehicle device specified by the arrival direction measuring device are determined. A dedicated narrow-area communication system including a roadside antenna for establishing a communication line with the on-vehicle device only when the communication device is in the communication area. 2. The arrival direction measuring device detects the position of the vehicle-mounted device based on a signal transmitted from the vehicle-mounted device and requesting the establishment of a communication link. 2. The dedicated narrow-area communication system according to claim 1, wherein a signal for permitting connection of a communication line is transmitted to an on-vehicle device having a position measured in a predetermined communication area of the roadside antenna. 3. An exclusive device according to claim 1, further comprising an on-vehicle device for transmitting a signal requesting the roadside antenna to establish a communication link after receiving an interrogation signal from the roadside antenna. Narrow area communication system. 4. The dedicated narrow-area communication system according to claim 3, wherein the on-vehicle device has identification information for identifying the on-vehicle device in a signal requesting the establishment of a communication link. 5. The direction-of-arrival measuring device associates with the identification information for identifying the vehicle-mounted device in the signal requesting the establishment of the communication link from the vehicle-mounted device, and sets the direction of arrival in a predetermined communication area of the roadside antenna. The position of the on-vehicle device that is located, and the roadside antenna transmits a communication line connection signal having identification information corresponding to the on-vehicle device specified in the predetermined communication area. Item 2. The dedicated narrow-area communication system according to Item 1. 6. The vehicle-mounted device, wherein after establishing a communication line with the roadside antenna, the radio wave arrival direction measuring device receives an information signal emitted from the vehicle-mounted device toward the roadside antenna and the vehicle-mounted device. 2. The dedicated narrow-area communication system according to claim 1, wherein a position of the vehicle-mounted device is detected, and a communication line between the vehicle-mounted device and the roadside antenna is disconnected immediately after the vehicle-mounted device passes through the communication area.