JP3051646B2 - Wireless toll collection 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 wireless toll collection system for collecting tolls by performing wireless communication between an antenna at a tollgate and a vehicle-mounted device mounted on a vehicle.

[0002]

2. Description of the Related Art In a conventional toll collection system for a toll road, a method is known in which a toll collector collects cash directly from a user at a toll booth, or causes a user to input cash into an automatic machine to collect a toll. Has been adopted. Therefore, the user had to stop at the toll booth and prepare cash.

On the other hand, as a wireless toll collection system that does not require the delivery of tolls at a toll gate, a wireless toll system is installed between an antenna unit attached to a gantry installed on a road and an on-board unit attached to a passing vehicle. A system for performing billing processing by communication has been developed.

FIG. 7 shows an example. A gantry 43 is laid on the road with two lanes 41 and 42 on one side,
Antenna units 44 and 45 are attached to the gantry 43. The gantry 43 has a vehicle detector 48 for detecting which lane the vehicle 46 is traveling on,
49 and 50 are attached. The vehicle 46 includes:
An in-vehicle device 47 is attached.

[0005] When a vehicle 46 having the above-described vehicle-mounted device 47 mounted thereon travels along the lane 41 and enters the communication area of the antenna unit 44, radio communication is performed between the antenna unit 44 and the vehicle-mounted device 47. A certain fee is charged.

The antenna units 44 and 45 are shown in FIG.
It is configured as shown in FIG. Antenna unit 44,
Reference numeral 45 denotes a transmitting antenna 51, a receiving antenna 52, a carrier oscillator 53, a data modulator 54, and a TDMA (Time Division Multiple Access) device 55.

FIG. 9 shows the antenna units 44 and 45.
2 shows a timing chart of data and carrier waves in FIG. The data transmitting antenna 51 performs data transmission and waits for a reply from the vehicle-mounted device 47 within a communication time slot. In this example, while waiting for a reply from the on-vehicle device 47, the data transmission antenna 51 is transmitting a return carrier wave from the on-vehicle device 47. Thereafter, while the TDMA device 55 is off, the data transmission antenna 51 does not transmit anything.

The communication area when the vehicle-mounted device 47 installed in the vehicle 46 passes through the system using the above-mentioned antenna units 44 and 45 is set as shown in FIG. The figure is a diagram of the communication area viewed from above.

In FIG. 10, antenna units 44,
45 is attached to the gantry 43 so as to be located above each of the lanes 41 and 42, and has communication areas 61 and 62, respectively. The TDMA device 55 causes the antenna units 44 and 45 to transmit data in order, thereby preventing interference with antennas in adjacent lanes.

[0010]

However, in the above-mentioned conventional system, the communication area differs depending on the vehicle type due to the mounting position of the vehicle-mounted device 47 and the influence of the windshield.
Vehicles with a wide communication area communicate with the antenna in the adjacent lane,
The lane in which the vehicle is detected by the vehicle detectors 48, 49, and 50 is different from the lane of the communicating antenna.
There has been a problem that the vehicle detected by the vehicle detectors 48, 49, and 50 is treated as a violating vehicle having no on-board device.

[0011] The present invention has been made in view of the above circumstances, and can reliably separate the communication area of each antenna unit.
It is an object of the present invention to provide a wireless toll collection system capable of performing communication between each antenna unit and a traveling vehicle without error and correctly executing a toll collection process.

[0012]

According to the present invention, a plurality of antenna units having a limited communication area located above a lane are installed, and when a vehicle equipped with a vehicle-mounted device passes through the communication area, In a wireless toll collection system that performs wireless communication between the antenna unit and the in-vehicle device to charge a passing vehicle, the antenna unit includes:
A carrier oscillator, a data modulator, a data transmission antenna, a carrier transmission antenna, a reception antenna, a switching device for alternately switching between data transmission and carrier transmission during transmission, and another adjacent antenna unit And a time-division multiplexing apparatus for performing time-division multiplexing access, wherein the communication area of another antenna unit is limited by the carrier wave transmission.

[0013]

The antenna unit has a function of transmitting a carrier wave as an interference wave in addition to data transmission. When one antenna unit is transmitting data using the data transmission antenna, the adjacent antenna unit transmits the carrier wave. The carrier is transmitted from the trusted antenna as an interference wave. This makes it possible to restrict the communication area by intentionally deteriorating the D / U ratio (desired wave to interference power ratio) of the communication area near the lane of the antenna transmitting the carrier. Therefore, the communication area of each antenna unit can be reliably separated,
Communication between each antenna unit and the traveling vehicle can be performed without error, and the toll collection process can be correctly executed.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of the entire wireless toll collection system according to the present invention. As shown in FIG.
A gantry 3 is straddled on the roads of the lanes 1 and 2, and the antenna units 11, 12 and 13 are attached to the gantry 3. These antenna units 11 to 13 are provided above lanes 1 and 2 and above lanes 1 and 2.
The gantry 3 is provided with vehicle detectors 14, 15, 16 for detecting which lane the vehicle 4 is traveling. The vehicle 4 has an in-vehicle device 5 attached thereto.

The antenna units 11 to 13 are connected to a ground unit at a tollgate, and transmit a call signal including an antenna number and location information when the vehicle 4 equipped with the vehicle unit 5 enters the communication area. To communicate with the on-vehicle device 5 to execute a toll collection process.

FIG. 2 shows the antenna units 11-13.
3 is a block diagram showing a configuration of a main part of FIG. As shown in FIG. 2, the antenna units 11 to 13 include a data transmitting antenna 21, a receiving antenna 22, a carrier transmitting antenna 23, a carrier oscillator 24, a modulator 25, and TDMA (Time Division Multiple Access). Device 2
6 and a transmission antenna switching device 27. The TDMA device 26 is connected to an antenna control device (not shown) on the ground unit. This antenna control device performs time management and performs the operation for all the antenna units 11 to 13.
Synchronized between. Also, the transmission antenna switching device 2
7 operates according to an instruction from the TDMA device 26, selects the data transmission antenna 21 at the time of data transmission, and selects the reception antenna 22 at the time of carrier wave transmission.

Next, the operation of the above embodiment will be described. When the vehicle 4 traveling in the lanes 1 and 2 enters the communication area, the vehicle detectors 14 to 16 detect the traveling position of the vehicle 4 and output detection data to the corresponding antenna units 11 to 13. The antenna units 11 to 13 transmit a call signal including an antenna number, location information, and the like, perform communication with the vehicle-mounted device 5 of the vehicle 4, and search for communication information from the antenna unit corresponding to the traveling position. In this case, the antenna units 11 to 13 corresponding to the traveling positions are determined in advance, and the corresponding information is tabulated in a main control device (not shown) on the ground unit side. Then, the traveling vehicle 4 and the communication information are matched, and the traveling vehicle 4 is specified.

FIG. 3 shows the antenna units 11-13.
6 is a timing chart showing transmission timings of data and a carrier wave in the inside. The carrier wave oscillator 24 is shown in FIG.
A high-frequency signal serving as a carrier is generated as shown in FIG. The modulator 25 is
During the data transmission period of the antenna unit, FIG.
The carrier is modulated by the data shown in (b) and output to the TDMA device 26. During the period (T1 + T2) during which the TDMA device 26 communicates with the on-vehicle device 5 of the vehicle 4, the TDMA device 26 outputs an "H" level signal as a switching signal shown in FIG. In the data transmission period T1, the modulated data signal input from the modulator 25 is output to the transmission antenna switching device 27 in the next reply waiting period T2 and in the carrier transmission period T3, the carrier wave from the carrier oscillator 24. This transmitting antenna switching device 2
7 selects the data transmission antenna 21 when the switching signal from the TDMA device 26 is at the “H” level.

Therefore, from the data transmitting antenna 21, as shown in FIG.
Then, in the next reply waiting period T2, a carrier wave for reply from the vehicle-mounted device 5 is transmitted. And TD
The MA device 26 communicates with the vehicle-mounted device 5 during a period (T1 + T2).
), The switching signal to the transmitting antenna switching device 27 is set to the “L” level. Thereby, the transmission antenna switching device 27 switches from the data transmission antenna 21 to the carrier wave transmission antenna 23 side. As a result, FIG.
As shown in (2), in the carrier wave transmission period T3, the carrier wave is transmitted from the carrier wave transmitting antenna 23 as an interference wave. In this carrier wave transmission period T3, the data transmission antenna 21 does not transmit anything.

As described above, during the carrier wave transmission period T 3, the carrier waves are transmitted from the carrier wave transmitting antenna 23, so that the antenna units 11, 12, 13 and the vehicle 4 are transmitted.
When communication is performed with the in-vehicle device 5 mounted on the vehicle, communication with the vehicle 4 traveling in a different lane can be prevented.

Hereinafter, the antenna units 11, 12, 13
The operation of separating the communication area between the vehicle and the vehicle 4 traveling in the lanes 1 and 2 will be described with reference to FIGS. FIG.
(A), (b) is a view of the communication area of the antenna units 11 to 13 as viewed from above, and FIG.
13 shows the operation timing. The transmission antenna switching device 27 of each of the antenna units 11 to 13 alternately switches the data transmission antenna 21 and the carrier transmission antenna 23 at regular time intervals as shown in FIG.
In this case, the antenna unit 11 and the antenna unit 1
3 and the data transmission antenna 21 at exactly the same timing.
The antenna unit 12 switches between the data transmitting antenna 21 and the carrier transmitting antenna 23 while maintaining a 180 ° phase difference with the antenna units 11 and 13. That is, while the antenna units 11 and 13 operate the data transmitting antenna 21, the antenna unit 12 operates the carrier transmitting antenna 23, and the antenna unit 1 operates at the next timing.
When 1, 13 operate the carrier transmitting antenna 23,
The antenna unit 12 operates the data transmission antenna 21.

FIG. 4A shows the antenna units 11 and 1.
3 shows the state of the communication area when the data transmission antenna 21 operates and the antenna unit 12 operates the carrier wave transmission antenna 23. The antenna units 11 and 13 have communication areas 31 and 32 by the data transmission antenna 21, respectively, and there are overlapping portions at the center as shown by the broken lines. , A carrier wave is transmitted as an interference wave, so that the communication areas 31 and 32
A carrier influence area 33 is generated therebetween. This communication area 31,
In the carrier-affected area 33 within the antenna unit 32, the D / U ratio (desired wave-to-interference wave power ratio) deteriorates, and the antenna units 11, 13
Communication between the vehicle and the vehicle is blocked. Thereby, the communication area 31 of the antenna unit 11 and the communication area 32 of the antenna unit 13 are clearly separated. Therefore, in this state,
The antenna unit 11 can communicate only with a vehicle traveling in the lane 1, and the antenna unit 13
Communication is possible only with the vehicle traveling on the vehicle.

FIG. 4B shows the antenna unit 1.
1 and 13 show the state of the communication area when the carrier transmitting antenna 23 operates and the antenna unit 12 operates the data transmitting antenna 21. The antenna unit 12 has a communication area 34 for the data transmission antenna 21. This communication area 34 includes both the lanes 1 and 2, but the antenna unit 1
The carrier wave transmitted from the carrier wave transmitting antennas 23 of the first and second carrier waves 13 causes the carrier influence area 3
5, 36 occur. Thus, the communication area 34 of the antenna unit 12 is only at the boundary between the lanes 1 and 2.
Therefore, in this state, communication is possible only with a vehicle traveling near the boundary between the lanes 1 and 2.

By alternately transmitting data between the antenna units 11 and 13 and the antenna unit 12 in this manner, communication with the vehicle 4 is enabled in all areas of the lanes 1 and 2, and the communication areas 31, 32 and 34 can be clearly separated. As a result, the vehicle detectors 14, 15,
16 and the antenna units 11, 12, and 13 can be optimized, and communication between the antenna units 11, 12, and 13 and the vehicle 4 traveling in each of the lanes 1 and 2 can be performed without error.

Since the carrier wave serving as an interfering wave is the same frequency as the carrier wave transmitted when waiting for a reply from the vehicle-mounted device 5, the vehicle-mounted device 5 transmits the reflected wave by modulating the carrier wave transmitted from the antenna. ) Does not affect the communication and the uplink from the vehicle-mounted device 5 to the antenna units 11 to 13.

In the above embodiment, the antenna units 11 to
13 shows a case where a data transmission antenna 21 and a carrier wave transmission antenna 23 are separately provided.
As shown in FIG. 6, a single data / carrier transmitting antenna 28 may be used as both antennas 21 and 23. In this case, a transmission output switching device 29 is used instead of the transmission antenna switching device 27, and data and a carrier are switched and output by one data / carrier transmission antenna. Thus, even when one data / carrier wave transmitting antenna 28 is used, communication with the vehicle 4 can be accurately performed in the same manner as in the above embodiment.

[0027]

As described above in detail, the antenna unit according to the present invention has a function of transmitting a carrier wave as an interference wave in addition to data transmission. When one antenna is transmitting data, the adjacent antenna is not transmitted. Controlling the communication area by transmitting a carrier wave as an interference wave and intentionally deteriorating the D / U ratio (desired wave to interference electric power ratio) of the communication area near the lane of the antenna transmitting the carrier wave Can be. Therefore, the communication area of each antenna unit can be clearly separated, and the communication between the antenna unit and the vehicle-mounted device of the vehicle traveling in each lane can be performed without error.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a wireless toll collection system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of the antenna unit in the embodiment.

FIG. 3 is a timing chart showing the operation of the antenna unit in the embodiment.

FIG. 4 is a diagram showing a communication area of the antenna unit in the embodiment.

FIG. 5 is a diagram showing operation timing of each antenna unit in the embodiment.

FIG. 6 is a block diagram showing a configuration of an antenna unit according to another embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a conventional wireless toll collection system.

FIG. 8 is a block diagram showing a configuration of an antenna unit in a conventional system.

FIG. 9 is a diagram showing operation timing of an antenna unit in a conventional system.

FIG. 10 is a diagram showing a communication area of an antenna unit in a conventional system.

[Explanation of symbols]

 1, 2 lane 3 gantry 4 vehicle 5 on-board unit 11-13 antenna unit 14-16 vehicle detector 21 data transmitting antenna 22 receiving antenna 23 carrier transmitting antenna 24 carrier oscillator 25 modulator 26 TDMA device 27 transmitting antenna switching device 28 Antenna for transmitting data and carrier wave 29 Transmission output switching device 31, 32, 34 Communication area 33, 35, 36 Carrier affected area

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G07B 15/00

Claims (2)

(57) [Claims] A plurality of antenna units having a limited communication area located above a lane are installed, and when a vehicle equipped with an on-vehicle device passes through the communication area, the antenna unit and the on-vehicle device communicate with each other. In a wireless toll collection system for performing wireless communication between users to charge a passing vehicle, the antenna unit includes a carrier wave oscillator, a data modulator, a data transmission antenna, a carrier wave transmission antenna, and a reception antenna. And a switching device for alternately switching between data transmission and carrier wave transmission during transmission, and a time division multiple access device for performing time division multiple access with another adjacent antenna unit. A wireless toll collection system characterized by limiting an area. 2. The wireless toll collection system according to claim 1, wherein the antenna for data transmission and the antenna for carrier wave transmission are shared.