JP2002042191A - Narrow area radiocommunication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a narrow area radiocommunication system capable of making an error of accounting against a tollgate-passing vehicle less by making an influence caused by a reflection and a leakage to an adjacent traffic lane loss. SOLUTION: When a vehicle approaching to a tollgate lane is detected by a vehicle detection part 3, a detection signal is fed to an ETC control part 6. A high frequency part 2 is controlled by controlling a wireless control part 3 from the ETC control part 6 by a processing state of an application to make to a transmittable state of a carrier wave and the ETC control part 6 simultaneously feeds a transmission control signal 7 to an antenna part 1 at a road side and the carrier wave is transmitted to a vehicle by a normal processing of the application. When the application is normally completed, a transmission control signal 7 is outputted from the ETC control part 6 to the antenna part 1 at the time of the completion and a transmission of the carrier wave from the antenna part is stopped. The ETC control part 6 simultaneously carries out an accounting of the vehicle against an accounting part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-stop toll collection system (hereinafter, referred to as an "ITS") which is one application example of an intelligent transport system (ITS).
Narrow-area wireless communication (hereinafter, DSRC: Dedicated) required for ETC: Electronic Toll Collection System, etc.
Short Range Communication)
A vehicle has entered a tollgate lane at a roadside wireless device (hereinafter referred to as a roadside device) installed at a tollgate or the like that performs wireless communication with a communication device (hereinafter, referred to as an onboard device) mounted on the vehicle side. A narrow-area wireless communication system in which a carrier wave is transmitted from a roadside antenna unit to perform application communication with an on-vehicle device only when the application communication is normally completed, or when a predetermined time elapses after vehicle entry is detected, the carrier wave transmission is stopped. .

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a configuration of a conventional example of a roadside device of a conventional ETC system. The roadside unit of the conventional ETC system shown in FIG. 3 performs modulation when transmitting a carrier wave to a vehicle entering a tollgate lane, with an antenna unit 1 performing transmission / reception in a 5.8 GHz band or the like,
Further, when a reception signal of a link request transmitted from an on-vehicle device mounted on a vehicle is received, a high-frequency unit 2 for demodulating the received signal and a transmission / reception signal control process for the high-frequency unit 2 are performed. A wireless control unit 3, a vehicle detection unit 4 for detecting entry of a vehicle into a tollgate lane, a charging processing unit 5 for calculating a charge for charging a vehicle passing through a tollgate, the wireless control unit 3, and the vehicle The ETC control unit 6 is connected to the detection unit 4 and the charging processing unit 5 and controls the entire processing of the ETC.

In the conventional ETC system configured as described above, the vehicle equipped with the vehicle-mounted device enters the tollgate lane and enters the communication range of the antenna unit 1, so that the vehicle-mounted device is transmitted from the antenna unit 1. Receives the data and issues a link request to the roadside device. At this time, the roadside machine detects vehicle entry by the vehicle detection unit 4 installed at the communication range boundary on the near side in the vehicle entry direction.

[0004] The high-frequency section 2 that has received the radio wave from the on-vehicle device demodulates the signal and passes it to the wireless control section 3. Wireless control unit 3
The ETC control unit 6 receiving the link request reception information from the vehicle and the vehicle detection information from the vehicle detection unit 4 accepts the link request from the vehicle-mounted device and starts communication. The roadside device obtains vehicle information such as an entrance through wireless communication with the on-vehicle device, calculates a charge in the charging processing unit 6, and performs toll collection processing.

[0005] In such a non-stop toll collection system, the roadside machine always transmits a carrier wave, and there is a problem that erroneous communication occurs due to reflection and leakage of a lane adjacent to the roadside antenna, and the roadside machine at the tollgate has a problem. The transmission power becomes unnecessarily large for communication with the vehicle-mounted device, and from this point, there is a possibility that the transmission power may interfere with radio waves in the adjacent lane. Therefore, a non-stop toll collection system that does not constantly transmit radio waves from the roadside device is disclosed in Japanese Patent Application Laid-Open No. H11-242762 (hereinafter, referred to as first publication).

[0006] In the case of the first publication, when an approaching vehicle detection sensor in front of a communication start position detects a vehicle entering the tollgate in a communication area with a tollgate road machine, the approaching vehicle detection sensor detects the vehicle. By transmitting a signal to the roadside system controller and sending a transmission start signal from the roadside system controller to the tollgate roadside unit, the tollgate roadside unit outputs radio waves to the communication area, communicates with the onboard unit, communicates In the area, when the passing vehicle detection sensor behind the communication end position detects a vehicle that has passed the tollgate on-road unit, the passing vehicle detection sensor sends a detection signal to the system control device, and the roadside system control device It is disclosed to send a transmission stop signal to a roadside machine. That is, in the case of the first publication, regarding the transmission of the carrier and the transmission stop control, the first detector detects the entry of the vehicle and transmits the carrier, and the second detector detects the absence of the vehicle. Thus, the transmission of the carrier is stopped.

In order to prevent radio wave interference between tollgate antennas in the case of a plurality of lanes, Japanese Patent Laid-Open No. 06-290 discloses
No. 323 (hereinafter referred to as "second publication") discloses that a center computer controls emission of radio waves in a lane, and a tollgate antenna in a certain lane uses a non-contact IC of a vehicle passing through the lane.
While communicating with the card, radio waves are not radiated from the tollgate antenna in the adjacent lane. Also, by making the carrier frequency different for each adjacent lane, if a frequency other than the carrier radiated by the tollgate antenna is received, the carrier radiated by itself and homodyne detection, and by passing through a band-pass filter, Exclude frequencies other than the carrier wave radiated by itself and their modulated waves,
Prevent the generation of interference waves. Further, by detecting the identity of the code transmitted from the contactless IC card and the code possessed by the autocorrelation circuit of the tollgate receiver, and demodulating only the received wave having the same identity, It is disclosed that the S / N of communication from a contactless IC card to a charge receiver is increased.

[0008]

The roadside device of the conventional ETC system as shown in FIG. 3 has a problem that erroneous communication occurs due to reflection / leakage of a lane adjacent to the antenna unit 1. In a wireless system using DSRC, in order to avoid radio wave interference, operation is performed at a frequency different from that of an adjacent lane, but carrier waves are always transmitted. In this case, due to the reflection caused by the nearby building and the shape and material of the passing vehicle, the onboard equipment communicates with the roadside machine in the adjacent lane, not the roadside machine that should originally communicate, and normal billing processing can be performed. The problem of disappearing occurs.

In order to prevent the interference of the radio wave with the adjacent lane, which occurs due to the constant transmission of the radio wave from the roadside device,
In the case of the first publication, as described above, in the communication area, when the passing vehicle detection sensor behind the communication end position detects the vehicle passing through the tollgate road machine, the detection is performed by the passing vehicle detection sensor. A signal is sent to the system controller, and the roadside system controller sends a transmission stop signal to the toll gate on-board unit. In this case, when the application with the on-board unit ends or after the vehicle enters the toll gate lane. Since the transmission of radio waves is not stopped after the elapse of a predetermined time, the interference of the radio waves is not sufficiently prevented, and thus erroneous communication with the roadside device on the adjacent lane cannot be completely avoided.

In addition, as disclosed in the above-mentioned second publication, radio waves are not radiated from a tollgate antenna in a nearby lane during non-contact IC card communication of a vehicle passing through a predetermined tollgate lane, The methods of making the carrier frequency different for each adjacent lane, or determining the match with the code of the transmission code toll field receiver of the non-contact IC using an autocorrelation circuit, are all applications to the onboard equipment. At the end or after the vehicle enters the tollgate lane, the radio transmission is not stopped after a predetermined time has elapsed, so that erroneous communication with the roadside device in the adjacent lane is inevitable, and thus normal billing processing is performed. There is a problem that you cannot do it.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. In an ETC system, when an application with an on-vehicle device is terminated, transmission of radio waves is stopped so that a radio wave of a roadside device from an adjacent lane can be transmitted. It is an object of the present invention to provide a short-range wireless communication system capable of reducing the possibility of erroneous communication due to reflection / leakage of an image and reducing errors in billing processing as much as possible.

[0012]

In order to achieve the above object, a short-range wireless communication system according to the present invention is arranged on a predetermined road side such as a tollgate on a toll road, and a vehicle enters the tollgate lane. A vehicle detection unit that outputs a detection signal when detecting a toll, a charging unit disposed at a predetermined position in the tollgate, and calculates a toll for a vehicle passing through the tollgate, and a vehicle entering the tollgate lane. Transmit a carrier to
And an antenna unit that receives a link request transmitted by the vehicle entering the tollgate lane by receiving the carrier, modulates the antenna unit when transmitting the carrier wave, and transmits the link request of the antenna unit. A high-frequency unit that demodulates a received signal; a radio control unit that controls transmission and reception of the carrier wave and the link request signal to the high-frequency unit; a vehicle detection unit; a charging unit; When each of the control units is connected to a detection signal of a vehicle entering the tollgate lane from the vehicle detection unit, the control unit controls the transmission of a carrier wave to the antenna unit or the wireless control unit, and the antenna unit controls the transmission of the carrier. When the link request signal from the vehicle is received, an application with the on-vehicle device mounted on the vehicle is performed in order to determine whether or not the vehicle can pass. Start the application communication, when the application process is completed, or when the vehicle detection unit elapses enters detected after a predetermined time of the vehicle to the tollgate lane,
An ETC control unit is provided for performing carrier wave transmission end control on the antenna unit or the wireless control unit and causing the charging processing unit to perform charging processing.

[0013] Therefore, when the vehicle detector detects the entry of the vehicle into the tollgate lane on the toll road, a detection signal is output to the ETC controller. When the ETC controller receives the detection signal, the ETC controller transmits the detection signal to the antenna unit. Alternatively, by controlling the wireless control unit and outputting a carrier transmission permission signal,
The carrier is transmitted from the antenna unit to the vehicle, or the radio control unit controls the high frequency unit to transmit the modulated carrier wave from the high frequency unit to the antenna unit. When the carrier transmitted from the antenna unit is received by the vehicle, the link request signal is received by the antenna unit by transmitting the link request signal from the vehicle, and the link reception signal is demodulated by the high frequency unit and transmitted through the radio control unit. By outputting to the ETC control unit, the roadside device starts application communication with the vehicle-mounted device, and when the application process ends normally, E
The TC control unit controls the antenna unit or the radio control unit to stop the transmission of the carrier wave, and at the same time, the ETC control unit controls the charging processing unit to perform the charging process for the vehicle passing through the tollgate lane. As a result, unnecessary carrier wave transmission from the antenna unit on the roadside machine side can be prevented, and the influence of radio wave reflection and leakage to the adjacent lane can be reduced, and errors in billing processing can be reduced as much as possible. Can be.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a short range wireless system according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a first embodiment of a narrow-area wireless system according to the present invention. The narrow-area wireless system shown in FIG. 1 is arranged on a road side such as a tollgate on a toll road. Yes, it will be a roadside machine.

The ETC roadside device shown in FIG. 1 modulates a carrier wave transmitted from the antenna unit 1 or receives a link request signal received from the vehicle-mounted device of the vehicle, which is received by the antenna unit 1. High frequency unit 2 for demodulation
A radio control unit 3 that performs transmission / reception signal control processing on the high frequency unit 2, a vehicle detection unit 4 that detects a vehicle entering a tollgate lane and outputs a vehicle detection signal to an ETC control unit 6. , An ETC that is connected to the wireless control unit 3, the vehicle detection unit 4, and the accounting unit 5 and that performs overall ETC processing.
And a control unit 6. Antenna unit 1 is ET
The transmission of the carrier is controlled by the transmission control signal 7 from the C control unit 6, and the transmission and reception in the 5.6 GHz band are performed as the carrier.

Next, the operation of the first embodiment according to the present invention configured as described above will be described. First,
A brief description will be given of a characteristic portion of the first embodiment. In the first embodiment, the transmission control of the antenna unit 1 is performed based on the vehicle entry and exit data from the vehicle detection unit 4 and the processing state of the application managed by the ETC control unit 6 (whether or not the processing is normally completed). I do. When the vehicle enters the lane of the tollgate, that is, the communicable range, the ETC control unit 6 permits the antenna unit 1 to transmit a carrier wave, and when the application ends normally (or for a certain period of time after detection of vehicle entry). After that,
In this case, which will be described later), the ETC control unit 6 sends a transmission control signal to the antenna unit 1 so as to stop carrier wave transmission.

Next, the first embodiment will be described in detail. The vehicle enters the tollgate lane and the vehicle detector 4
When detecting the entry of the vehicle, the detection signal is passed from the vehicle detection unit 4 to the ETC control unit 6. The ETC control unit 6 that has received the detection signal outputs a control signal to the wireless control unit 3 to cause the wireless control unit 3 to control the high-frequency wave unit 2, and from the high-frequency unit 2 to the antenna unit 1. The ETC control unit 6 outputs a transmission control signal 7 to the antenna unit 1 while modulating the carrier wave to make the carrier wave transmittable.
The antenna unit 1 that has received the transmission control signal 7 from the ETC control unit 6 starts transmitting a carrier wave to a vehicle that has entered the lane of the tollgate. The vehicle-mounted device of the vehicle that has received the carrier wave from the antenna unit 1 issues a link request to the roadside device. The antenna unit 1 of the roadside device that has received the link request outputs the link request received signal to the high frequency unit 2, which demodulates the signal under the control of the wireless control unit 3 and outputs the demodulated signal to the ETC control unit 6.

Thus, the ETC control unit 6 outputs a transmission control signal to the antenna unit 1 according to the application processing state (normal termination or not) managed by the ETC control unit 6, and Perform transmission control of 1.
The application communication with the vehicle-mounted device starts. When the application processing is completed normally, a carrier wave transmission stop signal is output from the ETC control unit 6 to the antenna unit 1, and the carrier wave transmission from the antenna unit 1 is stopped. As described above, in the first embodiment, when the vehicle detection unit 4 detects a vehicle entering the tollgate lane, a carrier is transmitted (in the case of the first publication, the first detector detects the vehicle). When the application communication ends, the transmission of the carrier is stopped.

When a vehicle without an ETC on-board device (ie, a non-ETC vehicle) enters the ETC lane, the vehicle detection unit 4 detects the vehicle entry and the detection signal is transmitted to the vehicle detection unit. 4 to the ETC control unit 6. As a result, the ETC control unit 6
And outputs the transmission control signal 7 to the antenna unit 1.

Therefore, transmission of a carrier wave from the antenna unit 1 to a non-ETC vehicle is started.
Since the on-board TC device is not mounted, application communication is not naturally started. In this case, when the detection signal is input to the ETC control unit 6 by the vehicle detection unit 4 detecting the vehicle that has entered the tollgate lane of the ETC lane, the ETC control unit 6 simultaneously has a built-in ETC lane. Start the timer. When the timer starts, for example, 200
After a predetermined time of ms (the current ETC application processing time is about 100 ms), the ETC control unit 6 stops transmission of the carrier to the antenna unit 1 so that the carrier is not transmitted to the radio control unit 3. High frequency section 2
, And transmits a transmission control signal 7 to the antenna unit 1 to control the antenna unit 1 to stop transmission of carrier waves to non-ETC vehicles. Thus, the transmission time of the carrier can be shortened. Along with this,
For example, if one lane is congested,
Although the carrier is still transmitted, in the first embodiment, even at the time of congestion, the maximum is 200 ms,
The probability that adjacent lane carriers will overlap is significantly reduced.

Therefore, even if the non-ETC vehicle enters the toll lane, the carrier can be transmitted after a lapse of a predetermined time, so that the unnecessary transmission of the carrier from the roadside machine can be performed. Therefore, the influence of the reflection or leakage of the carrier wave to the adjacent oblique line can be reduced as much as possible. Along with this, it is possible to normally perform the charging process for the vehicle that makes the tollgate currency.

As described above, in the first embodiment, when the vehicle detection unit of the roadside machine fetches a signal for detecting entry of a vehicle and outputs the signal to the ETC control unit 6, the ETC control unit 6 Carrier wave transmission is controlled, carrier wave transmission is started at the vehicle entry timing, and carrier wave transmission is stopped at the normal end of the application, so unnecessary carrier wave transmission from the roadside machine is minimized. can do. Therefore, it is possible to minimize the probability that the vehicle receives a carrier wave from an adjacent lane, to reduce the possibility of erroneous communication, and to minimize errors in the charging process for the vehicle.

Next, a second embodiment of the present invention will be described. FIG. 2 is a block diagram showing the configuration of the second embodiment. In the second embodiment shown in FIG. 2, unlike the first embodiment in which the carrier transmission control is directly controlled from the ETC control unit 6 to the antenna unit 1, the ETC control unit 6 transmits the carrier to the radio control unit 3. The control signal 7 is output. Other parts are configured in the same manner as in FIG. 1, and the same parts as those in FIG. As described above, even when the ETC control unit 6 outputs the transmission control signal 7 of the carrier to the wireless control unit 3, the same effect as in the first embodiment can be obtained.

[0024]

As described above, according to the present invention, the transmission control of the antenna unit is performed by using the detection signal of the vehicle entry from the vehicle detection unit and the transmission control signal generated by the ETC control unit according to the processing state of the application. To eliminate unnecessary carrier wave transmission from the roadside antenna,
The influence of reflection and leakage to the adjacent lane can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of a short-range wireless communication system according to the present invention.

FIG. 2 is a block diagram showing a configuration of a second embodiment of the short range wireless communication system according to the present invention.

FIG. 3 is a block diagram illustrating a configuration of a conventional narrow-area wireless communication system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Antenna part, 2 ... High frequency part, 3 ... Wireless control part, 4 ... Vehicle detection part, 5 ... Billing processing part, 6 ... ET
C control section 7, transmission control signal.

Claims (2)

[Claims] 1. A vehicle detection unit which is arranged on a predetermined road side such as a tollgate on a toll road and outputs a detection signal when detecting the entry of a vehicle into the tollgate lane, and is arranged at a predetermined position of the tollgate. A charging processing unit for calculating a toll of a vehicle passing through the tollgate, transmitting a carrier wave to a vehicle entering the tollgate lane, and receiving a carrier wave from a vehicle entering the tollgate lane. An antenna unit that receives a link request to be transmitted by performing the above, a high-frequency unit that performs modulation at the time of transmission of the carrier wave of the antenna unit, and demodulates a received signal of the link request of the antenna unit, A wireless control unit that controls transmission and reception of the carrier wave and the received signal of the link request, respectively, and is connected to the vehicle detection unit, the charging unit, and the wireless control unit, respectively. When a detection signal of a vehicle entering the tollgate lane is input from the vehicle detection unit, transmission control of a carrier wave is performed to the antenna unit or the wireless control unit, and the antenna unit transmits the link request signal from the vehicle. When receiving the application, the application communication with the vehicle-mounted device mounted on the vehicle is started in order to perform the process of determining whether or not the vehicle can pass, and the carrier wave is transmitted to the antenna unit or the wireless control unit at the end of the application process. An ETC control unit that controls transmission termination and causes the charging processing unit to perform charging processing. 2. The ETC control unit, when the vehicle detection unit detects that a vehicle without an on-board ETC device has entered the tollgate lane and receives a detection signal from the vehicle detection unit, 2. A transmission control signal is transmitted to the antenna unit at the same time as a timer is started to transmit a carrier to the vehicle, and transmission of the carrier to the antenna unit is stopped after a lapse of a predetermined time. A short-range wireless communication system according to claim 1.