JP3417341B2 - Roadside-vehicle communication onboard equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle-to-vehicle communication device for two-way communication with a roadside device installed on the road side, and particularly when traveling in a predetermined communication section in an automatic toll collection system or the like. The present invention relates to a vehicle-to-vehicle communication vehicle-mounted device having a control function of performing bidirectional communication only with the vehicle.

[0002]

2. Description of the Related Art As publications relating to conventional road-vehicle communication systems, reference is made to, for example, JP-A-2-183635 and JP-A-8-27403. As a communication area determination method in the conventional road-vehicle communication system,
For example, in Japanese Unexamined Patent Publication No. 2-183635, the arithmetic processing means of the vehicle-mounted receiving device determines whether or not it is a communicable region based on the level of the first modulated wave component, and the same as the frequency of the amplitude modulation signal. The phase of the frequency clock and the phase of the second modulation wave component are compared to detect in which region of the split beam the vehicle is located, and the amplitude of the second modulation wave component is detected. A system has been proposed which detects a drop in the level of the second modulated wave component, determines the communication area, and ensures high-quality communication with a simple configuration.

Further, as a control method for starting communication between an in-vehicle device and a roadside device, for example, in Japanese Patent Laid-Open No. 8-27403, mounting position information of an in-vehicle antenna is received from an in-vehicle communication device, and the mounting position information is detected. A method in which the relative positional relationship between the roadside antenna and the vehicle-mounted antenna is calculated, the relative position between the roadside antenna and the vehicle-mounted antenna is detected, and when the detected relative position is the relative positional relationship, transmission from the roadside antenna is started. Is proposed.

[0004] Toll charges for vehicles passing through toll roads,
In an automatic toll collection system that collects by wireless communication, a carrier wave is transmitted from a roadside device to a vehicle traveling in a predetermined communication section, an in-vehicle device mounted on the vehicle receives the carrier wave, and a response signal is received from the in-vehicle device. The toll collection process is performed by receiving the.

The road-vehicle communication vehicle-mounted device in the conventional automatic toll collection system only needs to perform the bidirectional communication operation only when the vehicle travels within the predetermined communication section, and needs to perform the bidirectional communication operation in the other sections. There is no.

Further, in order to prevent unnecessary electric waves from being transmitted in response to noise while the vehicle is traveling on a road other than the predetermined communication section and to reduce power consumption, when entering the predetermined communication section, It has a function of enabling bidirectional communication and controlling the bidirectional communication to be stopped when the vehicle leaves a predetermined communication section.

Then, a carrier wave of a predetermined frequency is transmitted from the roadside device installed in the predetermined communication section to the vehicle-mounted apparatus, and the vehicle-mounted apparatus detects the reception level of the carrier wave to detect the carrier within the predetermined communication section. Detects whether or not you entered,
On-off control is performed for the bidirectional communication operation with the in-vehicle device.

FIG. 4 is a block diagram showing the structure of a conventional vehicle-mounted device. Referring to FIG. 4, a reception unit 11 that receives a carrier wave S1 transmitted from a roadside device by an antenna 15 and outputs reception data S2, a reception level detection unit 12 that detects a reception level of a reception signal, and a reception level And an operation control section 13 that outputs a control signal 6 for turning on / off the operation of the response transmission section 14.

The response transmission section 14 receives the received data S2.
In response to the control signal S5 from the operation control unit 13, and includes a circuit for generating a response signal and a circuit for transmitting the response signal.

The receiving unit 11 is constantly operating while the vehicle is running, and is ready to receive the carrier wave transmitted from the roadside unit.

The operation control unit 13 is, for example, as shown in FIG.
As indicated by the solid line in (a), it is determined that the reception level is within the communication section when the reception level exceeds a predetermined threshold,
A control signal S6 for turning on the operation of the response transmission unit 14 is transmitted.

When the response transmission unit 14 is activated, bidirectional communication is possible between the vehicle-mounted device and the roadside device, and a response signal is transmitted according to the carrier wave. On the other hand, when the reception level is less than the threshold value, it is determined that it is outside the predetermined communication section, and a control signal for stopping the operation of the response transmission unit 14 is sent to stop the bidirectional communication.

In this way, by controlling the operation of the response transmitter 14 according to the reception level of the carrier wave, the bidirectional communication between the vehicle-mounted device and the roadside device (signal between the roadside device and On / off control.

[0014]

As described above, in the conventional road-vehicle communication vehicle-mounted device, on / off control of the response transmitter of the vehicle-mounted device is performed based on the reception level of the continuous carrier wave transmitted from the roadside device. Thus, the bidirectional communication is controlled only when traveling within the predetermined communication section.

However, when the carrier wave transmitted from the roadside device is not continuous but an intermittent burst wave, the reception level detected by the vehicle in the communication section is as shown in FIG.
As indicated by a broken line in (a), since the burst wave fluctuates in response to the interruption, accordingly, the response transmission section 14 repeats the operating state / stop state, as shown in FIG. 5 (c).
There is a problem that the bidirectional communication operation cannot be normally controlled on / off.

Therefore, the present invention has been made in view of the above problems, and an object thereof is to correctly recognize a communication section even if a carrier wave transmitted from a roadside device is a burst wave and to perform normal operation. An object of the present invention is to provide an on-vehicle communication device for road-to-vehicle communication capable of reliably and stably controlling operation of bidirectional communication.

[0017]

An on-vehicle vehicle-to-vehicle communication system according to the present invention which achieves the above object, has a reception level obtained by receiving a carrier wave transmitted from a roadside device installed on a road side within a predetermined communication section. On the basis of both the frame synchronization obtained by the reception and demodulation, it is detected whether or not it is a predetermined communication section, and on / off control of the bidirectional communication operation is performed according to the detection result.

More specifically, the present invention receives and demodulates a carrier wave consisting of a burst wave transmitted from a roadside device installed on the road side within a predetermined communication section, and synchronizes with the received data and the received data. A receiving unit that outputs a clock signal, receives the received data and the clock signal output from the receiving unit, outputs a first detection signal when a change point of the received data is detected, and outputs a frame from the received data. Reception detection means for outputting a second detection signal when a pattern for synchronization is detected, and the first detection signal being output from the reception detection means,
Moreover, when the second detection signal is output a predetermined number of times in a predetermined cycle, a response transmission means for transmitting a response to the roadside machine is operated to output a control signal for enabling bidirectional communication. At the same time, after the output of the control signal is started, the operation of the response transmission means is performed when a predetermined time has elapsed without either or both of the first and second detection signals being output. Control signal generating means for outputting a control signal for stopping.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In a preferred embodiment of the present invention, a road-vehicle communication vehicle-mounted device that performs two-way communication with a roadside device installed on a road side within a predetermined communication section is a burst wave transmitted from the roadside device. Receiving means (1) for receiving and demodulating the carrier wave, and outputting a first detection signal (S4) when a change in the demodulated reception data is detected, and at the same time using the pattern for frame synchronization from the reception data. Operation of reception detection means (2) that outputs a second detection signal (S5) when a certain unique word is detected, response transmission means (4) that transmits a response to a roadside device, and response transmission means (4) Means for controlling the on / off of the first and second detection signals (S) from the reception detecting means (2).
4, while frame synchronization is being established based on S5),
Control signal generation means (3) for outputting a control signal (S6) for turning on the bidirectional communication operation to the response transmission means (4).
And ,.

In the embodiment of the present invention, the reception detecting means (2) includes the received data demodulated by the receiving means (1) and a clock signal extracted from the received data by the receiving means (1). Is input, the received data is fetched by a predetermined bit, which is compared with a predetermined pattern for change detection, and when the change point of the received data is detected from the comparison result, The first detection means (21 in FIG. 2,
22), the received data and the clock signal are input, the received data is fetched by a predetermined bit, and this is compared with a predetermined frame synchronization pattern. As a result of the comparison, both are If they match, the second
Second detection means (23 and 24 in FIG. 2) for outputting the detection signal (S5) of FIG.

In the embodiment of the present invention, when the control signal generating means (3) and the first detection signal (S4) are input, the first output signal is activated, and the first detection signal is Counting means (31) for deactivating the first output signal when a predetermined time elapses without inputting the next first detection signal after being input;
When the detection signal (S5) is input a predetermined number of times in a predetermined cycle, the frame synchronization of the carrier wave is determined to activate the second output signal, and the second detection signal is predetermined. Frame synchronization determining means (32) that deactivates the second output signal by determining that the frame is out of synchronization when the predetermined period of time has been interrupted, the first output signal, and the second output signal. Based on the value of the control signal (S) to turn on the bidirectional communication operation with the roadside device.
Circuit means (33) for outputting 6), and based on the demodulated received data, it is determined that the period during which frame synchronization is established is within the communication section, and a response is sent to the roadside device. Is turned on.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to describe the embodiment of the present invention described above in more detail, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an in-vehicle device according to an embodiment of the present invention. Referring to FIG. 1, a carrier wave S1 transmitted from a roadside device is received by an antenna 5, and received data S2 and a clock signal S3 synchronized with the received data are received.
ON / OFF control of the operation of the reception unit 1 that outputs the following, the reception detection unit 2 that detects whether or not it is within a predetermined communication section based on the reception data S2, and the response transmission unit 4 based on the detection result of the reception detection unit 2. A control signal generator 3 for outputting a control signal S6,
Is equipped with.

The carrier wave transmitted from the roadside device is a TDMA (Time Division Multiple Acce
ss; time division multiple access) signal wave.

The response transmission unit 4 includes a circuit for generating a response signal according to the received data and a circuit for transmitting the response signal, and turns on / off the operation according to the control signal S6.
When turned on, vehicle information and the like are transmitted to the roadside device as a response signal according to the reception data S2.

The receiving unit 1 is a carrier wave S composed of burst waves.
1 is received and demodulated, the demodulated received data S2 and the clock are extracted, and a clock signal S3 synchronized with the received data is output.

The reception detection unit 2 receives the reception data S2 and the clock signal S3 output from the reception unit 1, detects a change point of the reception data and the presence / absence of a unique word (UW), and outputs a detection signal 1S4. .

When a vehicle enters a predetermined communication section and receives a carrier wave, for example, the received data S2 received changes as shown in FIG. 2 (FIG. 2A). It is possible to detect the entry into the communication section by detecting the presence / absence of the presence and the presence of a unique word consisting of a predetermined N-bit reference pattern from the received data.

Further, if the vehicle is outside the predetermined communication section, the received data is not received, and the change point of the received data and the reference pattern cannot be detected.

As described above, by detecting the change point of the received data and the presence or absence of the reference pattern, it is possible to detect whether or not the carrier wave can be received, that is, whether or not the vehicle has entered the predetermined communication section. .

The reception detecting section 2 outputs the first detection signal S4 (FIG. 2B) when the reception data changes from "0" to "1" or from "1" to "0".

When a unique word based on the N-bit reference pattern is detected from the received data, the second detection signal S5 (FIG. 2 (c)) is output.

In the control signal generator 3, the reception detector 2 outputs the first detection signal S4 for a certain period of time, and the second detection signal S5 is continuously detected every frame for a predetermined number of times. When it is determined that the frame synchronization is established, the control signal S6 is turned on, the response transmission unit 4 is operated, and the bidirectional communication operation is performed (FIG. 2).
(D)).

Further, the reception detecting section 2 causes the first detection signal S4
Even after a certain time has passed after the output of
When the reception detection unit 2 does not output the second detection signal S5 and the frame synchronization is lost without outputting the first detection signal S4, the control signal 6 is turned off and the operation of the response transmission unit 4 is stopped. Then, the bidirectional communication is stopped.

In this embodiment, the response transmitting section 4 is operated when the control signal S6 is at "1" level, and the response transmitting section 4 is stopped when the control signal S6 is at "0" level.

Further, the reception detection unit 2 causes the first detection signal S4
Is not output, and the reception detection unit 2 does not output the second detection signal S5, that is, the state in which the carrier wave cannot be received continues for a predetermined time T longer than one frame period of the received data. In addition, the control signal S6 is changed from the "1" level to the "0" level.

As described above, by detecting the change point of the reception data demodulated by the receiving unit 1 and the reference pattern, it is determined whether or not the carrier wave can be received, that is, whether or not the vehicle has entered the predetermined communication section. By adopting the determination configuration, the operation control of the response transmission unit 4 can be normally and reliably performed even in the case of noise other than the carrier wave transmitted from the roadside device.

FIG. 3 is a diagram showing an example of the configuration of the reception detector 2 and the control signal generator 3 shown in FIG. Here, the reception detection unit 2 uses the 2-bit shift register circuit 21.
It has a 2-bit comparison circuit 22, an N-bit shift register circuit 23, and an N-bit comparison circuit 24.

The control signal generator 3 includes a counter circuit 31.
And a frame synchronization circuit 32 and an AND circuit 33.

The 2-bit shift register circuit 21 sequentially takes in the received data S2 serially output from the receiving unit 1 according to the clock signal S3 and outputs it as 2-bit parallel data.

The 2-bit comparison circuit 22 receives the 2-bit parallel data output from the 2-bit shift register circuit 21, and outputs the 2-bit parallel data as "01",
By comparing with the reference pattern of “10”, it is detected that the received data changes from “0” level to “1” level and from “1” level to “0” level. A pulse having one cycle width of the signal S3 is output as the first detection signal S4.

Further, the N-bit shift register circuit 23
Is the reception data S2 serially output from the receiving unit 1.
Are sequentially taken in according to the clock signal S3 and output as N-bit parallel data.

The N-bit comparison circuit 24 receives the N-bit parallel data output from the N-bit shift register circuit 23 and compares the N-bit parallel data with a predetermined N-bit unique word (UW) reference pattern. As a result, the position of the UW is detected from the received data, and when the UW is detected, a pulse having one cycle width of the clock signal S3 is output as the detection signal 2S5.

The first detection signal S4 output from the 2-bit comparison circuit 22 is supplied to the counter circuit 31 of the control signal generator 3.

The counter circuit 31 has a first detection signal S4.
Is set to output "1" level, and when the first detection signal S4 reaches a predetermined count value of the input cycle, the output is reset to "0" level. It That is, the counter circuit 31 functions as a timer counter, starts counting time after the first detection signal S4 is input, and outputs the next first detection signal S4 even if a predetermined period has elapsed. If not input, the output is reset.

The count value (timer value) set in the counter circuit 31 is set to a sufficient time after the last change point of the received data is detected, that is, a time sufficiently longer than one frame period of the received data. It

The second detection signal S5 output from the N-bit comparison circuit 24 is supplied to the frame synchronization circuit 32 of the control signal generation section 3.

The frame synchronization circuit 32 judges that the frame synchronization is established when the input of the second detection signal S5 is continuously detected a predetermined number of times for each frame, and sets the level to "1". When the second detection signal S5 is no longer detected several times in a predetermined cycle, it is determined that the frame synchronization has been lost, and a "0" level is output. The frame synchronization circuit 32 receives the second detection signal S5, counts up, and outputs a "1" level as an overflow signal when counting a predetermined number of times, and a counter outputs a "1" level as an overflow signal. After that, when clocking is started and the second detection signal S5 is not input for a time period corresponding to several frame periods, that is, when the time is interrupted, a timeout occurs and the output of the counter is set to "0".
It can be configured with a circuit for resetting to a level. In addition, the counter that counts the second detection signal S5 is configured to detect the second detection signal S5 before the overflow occurs.
When the next second detection signal S5 is not input within a period corresponding to the cycle (frame cycle) of the second detection signal S5 after 5 is input, the count value is cleared to 0. You may comprise.

As a result, the frame synchronizing circuit 32 stops the input of the detection signal 2S5 after the vehicle goes out of the communication section after the detection signal 2S5 is once input, and enters the other communication section again and the detection signal 2S5 is received. When it is input, it is avoided to erroneously determine that the frame synchronization has been established after continuously counting this and going out of the other communication section.

The output of the counter circuit 31 and the output of the frame synchronization circuit 32 are supplied to the AND circuit 33.

The AND circuit 33 sets the control signal 6 to the "1" level when both the output of the counter circuit 31 and the output from the frame synchronization circuit 32 are at the "1" level to operate the response transmission section 4. Allows two-way communication, then
When either or both of the output of the counter circuit 31 and the output from the frame synchronization circuit 32 become "0" level, the control signal S6 is changed from "1" level to "0" level, and the response transmission unit 4 Stop the operation and stop the bidirectional communication. A logical product circuit is used because the output of the counter circuit 31 and the output of the frame synchronization circuit 32 are active when "1". However, if the output is active when "0", a logical sum circuit is used. Thus, the present invention is not limited to such an AND circuit.

As described above, since the operation time of the response transmission unit 4 can be controlled to a necessary minimum within the predetermined communication section, even when the vehicle is stalled for a long time in the predetermined communication section due to the influence of traffic congestion or the like, Useless power consumption can be prevented.

It is to be noted that means for detecting a change point of demodulated data of a carrier wave to detect whether or not a predetermined communication section is entered,
A means for detecting whether the demodulated data of the carrier wave is in sync with the frame to detect whether or not it has entered the predetermined communication section, and on / off control the bidirectional communication operation based on the detection results of both means. Thus, the operation can be surely controlled.

The present invention can also be applied to a mobile phone, a PHS (Personal Handy Phone System) terminal or the like to reduce the power consumption of the battery. That is,
It demodulates the received data from the base station, detects changes in the received data, and when the frame synchronization is secured, turns on the transmission circuit of the mobile station to enable bidirectional communication with the base station. Therefore, power consumption can be reduced.

[0055]

As described above, according to the present invention, the change point detection of the reception data obtained by demodulating the carrier wave transmitted from the roadside device and the frame synchronization of the reception data obtained by demodulating the carrier wave are performed. By detecting both, it is possible to normally and reliably detect whether or not the vehicle has entered the predetermined communication section, and it is possible to reduce power consumption by stopping the bidirectional communication operation outside the predetermined communication period.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an in-vehicle device according to an embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the embodiment of the present invention.

FIG. 3 is a block diagram showing an example of configurations of a reception detection unit 2 and a control signal generation unit 3 according to an embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional vehicle-mounted device.

FIG. 5 is a diagram for explaining the operation of a conventional vehicle-mounted device.

[Explanation of symbols]

1 receiver 2 Reception detector 3 Control signal generator 4 Response transmitter S1 carrier wave S2 received data S3 clock signal S4 First detection signal S5 Second detection signal S6 control signal 21 2-bit shift register circuit 22 2-bit comparison circuit 23 N-bit shift register 24 N-bit comparison circuit 31 counter circuit 32 frame synchronization circuit 33 AND

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Claims (7)

(57) [Claims] 1. A vehicle-to-vehicle communication device for bidirectional communication with a roadside device installed on a road side within a predetermined communication section, wherein a carrier wave composed of a burst wave transmitted from the roadside device is received. Receiving means for demodulating; a first detection signal is output when the demodulated received data is monitored and a predetermined change is detected, and a second detection signal is output when a pattern for frame synchronization is detected from the received data. A reception detecting means for outputting a detection signal, a response transmitting means for transmitting a required response to the roadside device according to the received data, and a means for controlling ON / OFF of the operation of the response transmitting means, Based on the first and second detection signals from the reception detection means, a control signal generation for outputting a control signal for turning on the bidirectional communication operation to the response transmission means while frame synchronization is established. A vehicle-to-vehicle communication vehicle-mounted device characterized by comprising: 2. A receiving means for receiving and demodulating a carrier wave composed of a burst wave transmitted from a roadside device installed on the road side within a predetermined communication section, and outputting received data and a clock signal synchronized with the received data. And receiving the received data and the clock signal output from the receiving means, outputting a first detection signal when a change point of the received data is detected, and detecting a frame synchronization pattern from the received data. Reception detection means that outputs a second detection signal at times, and the first detection signal is being output from the reception detection means, and the second detection signal has a predetermined cycle. When a predetermined number of times is output, the response transmission means for transmitting a response to the roadside device is operated to output a control signal that enables bidirectional communication, and also outputs the control signal. After the start, when either one or both of the first detection signal and the second detection signal are not output and a predetermined time has elapsed, control for outputting a control signal for stopping the operation of the response transmission means A vehicle-to-vehicle communication vehicle-mounted device comprising: a signal generating unit. 3. The reception detection means receives the reception data demodulated by the reception means and a clock signal extracted from the reception data by the reception means as inputs, and sets the reception data to a predetermined value. A first detecting means for fetching bits, comparing this with a predetermined change detection pattern, and outputting the first detection signal when a change point of the received data is detected from the comparison result; , Receiving the received data and the clock signal as an input, fetching the received data by a predetermined number of predetermined bits, and comparing this with a predetermined frame synchronization pattern,
The vehicle-to-vehicle communication device according to claim 1 or 2, further comprising: a second detection unit that outputs the second detection signal when the two match as a result of the comparison. 4. The control signal generation means activates a first output signal when the first detection signal from the first detection means is input, and the first detection signal is input. After that, the counting means for deactivating the first output signal when a predetermined time elapses without inputting the next first detection signal, and the second detection means from the second detection means. When the second detection signal is input a predetermined number of times in a predetermined cycle, the frame synchronization of the carrier is determined to activate the second output signal, and the second detection signal is predetermined. If the frame is interrupted for a predetermined period, it is determined that the frame is out of sync and the second
A frame synchronization determination means for deactivating the output signal of the second output signal, and a on-control of the bidirectional communication operation with the roadside device based on the values of the first output signal and the second output signal. 4. The vehicle-to-vehicle communication vehicle-mounted device according to claim 3, further comprising: a circuit unit that outputs a control signal. 5. The circuit means comprises: the first output signal;
The vehicle-to-vehicle communication vehicle-mounted device according to claim 4, comprising a gate circuit that performs a logical product with the second output signal. 6. An on-road vehicle-to-vehicle communication device that performs two-way communication with a roadside device installed on a road side within a predetermined communication section, receives a carrier wave transmitted from the roadside device, and demodulates the carrier wave. Receiving means for outputting received data, and reception detecting means for detecting whether or not it is within the predetermined communication section by detecting a change point of the received data and a predetermined unique word for frame synchronization from the received data. And a control signal generating means for outputting a control signal for controlling ON / OFF of the bidirectional communication operation based on the detection result of the reception detecting means. 7. Receiving means for receiving and demodulating a carrier wave transmitted from a base station, and outputting received data and a clock signal synchronized with the received data, and the received data and clock signal output from the receiving means. Receiving detection means for receiving a first detection signal when detecting a change point of the reception data and outputting a second detection signal when detecting a pattern for frame synchronization from the reception data; When the first detection signal is output from the reception detection means and the second detection signal is output a predetermined number of times in a predetermined cycle, a response is transmitted to the base station. One of the first and second detection signals is output after starting the output of the control signal as well as outputting a control signal that operates the transmitting means to enable bidirectional communication. When both of the predetermined time a predetermined without being output has elapsed, the mobile terminal apparatus characterized by comprising a control signal generating means for outputting a control signal for stopping the operation of said transmission means.