JP6750566B2 - Wireless device - Google Patents

Description

The present invention relates to communication technology, and more particularly to a wireless device that performs wireless communication.

Communication systems such as ETC (Electronic Toll Collection system), DSRC (Dedicated Short Range Communication), and wireless LAN (Local Area Network) have been put into practical use. In such a vehicle-mounted wireless terminal that can use a plurality of wireless communication systems, the wireless communication system is switched according to the state of the vehicle (see, for example, Patent Document 1).

JP, 2004-80420, A

Generally, a communication device compatible with ETC or DSRC and a wireless device compatible with wireless LAN are configured separately. When both communication bands are adjacent to each other, the use of wireless LAN may interfere with ETC or DSRC.

The present invention has been made in view of such circumstances, and an object thereof is to provide a technique for reducing the influence on another communication system.

In order to solve the above problems, a radio device according to an aspect of the present invention is a radio device in a first communication system that uses a first band, and a communication unit that performs communication using the first band, Monitors the usage status of the second band that is used in the second communication system that is different from the first communication system that uses the first band and that is different from the first communication system that uses the first band. And a usage state of a third band which is a third band different from the first band used by the communication unit and which can be used by the first communication system using the first band. A second monitoring unit and a control unit that causes the communication unit to change from using the first band to using the third band when the usage status monitored by the first monitoring unit changes from unused to used ..

It should be noted that any combination of the above constituent elements, and the expression of the present invention converted between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

According to the present invention, it is possible to reduce the influence on another communication system.

FIG. 1 is a diagram showing a configuration of a vehicle according to a first embodiment. It is a figure which shows the structure of the radio|wireless apparatus of FIG. 3A to 3D are diagrams showing an outline of processing by the wireless device in FIG. 3 is a flowchart showing a processing procedure by the wireless device of FIG. 2. FIG. 9 is a diagram showing a configuration of a wireless device according to a second embodiment.

(Example 1)
Before specifically describing the present invention, the knowledge on which the examples are based will be described. Example 1 of the present invention relates to a wireless device mounted on a vehicle or the like. The wireless device can execute communication by wireless LAN. The wireless LAN uses a frequency band of W56 (5470 MHz to 5725 MHz) (hereinafter, referred to as “first band”) that can be used outdoors in Japan. When a wireless device mounted on a vehicle and a terminal device such as a smartphone brought in the vehicle are connected, communication in the first band is performed. In order to stabilize this communication with high throughput, for example, the occupied band in the wireless LAN is expanded. On the other hand, narrow-range communication systems for transportation vehicles such as DSRC and ETC use a frequency band of W58 (5770 MHz to 5850 MHz) (hereinafter, referred to as "second band") in Japan. Here, the second band is adjacent to the first band. When the wireless LAN is called the first communication system, the short-range communication system for transportation vehicles is called the second communication system.

When communication by DSRC/ETC and communication by wireless LAN are performed in a narrow space inside the vehicle, a signal of the wireless LAN (hereinafter, referred to as “first signal”) causes radio wave interference on the DSRC/ETC side. Sometimes. This may cause a situation in which communication by DSRC/ETC is not performed correctly. When using the wireless LAN in the first band outdoors, radar detection is provided for a certain period in order to avoid interference with weather radar signals or marine radar signals. It is obligatory to have a DFS (Dynamic Frequency Selection) function that temporarily stops the wave. However, sharing of DSRC/ETC and wireless LAN is not specified.

To prevent radio wave interference between the DSRC/ETC and the wireless LAN in the vehicle, it is effective to separate the communication device and the wireless device from each other, but it is necessary to separate them by several hundred meters, which means that the device is in the vehicle. Considering this, this is impossible. On the other hand, it is effective to stop the communication of the wireless LAN during the communication of DSRC/ETC, but the stable communication is not performed. That is, stable communication without radio wave interference in DSRC/ETC and high-throughput stable wireless LAN communication with expansion of occupied bandwidth are contradictory. Apart from this, it is possible to move to another frequency band such as the 2.4 GHz band and execute the wireless LAN communication during the DSRC/ETC communication, but the same or neighboring channel in the wireless LAN May cause radio wave interference.

FIG. 1 shows the configuration of a vehicle 500 according to the first embodiment. The vehicle 500 includes the wireless device 100, the terminal device 200, and the communication device 300, and the roadside unit 400 is provided outside the vehicle 500. The wireless device 100 is a communication device in a wireless LAN that uses the first band. The wireless device 100 is built in, for example, a car navigation system device (not shown) mounted on the vehicle 500. The terminal device 200 is a communication device such as a smartphone brought into the vehicle by an occupant of the vehicle 500. Although the terminal device 200 is compatible with communication systems other than the wireless LAN, only the wireless LAN is focused here. The terminal device 200 communicates with the wireless device 100 in the first band.

The communication device 300 is a communication device in DSRC/ETC that uses the second band. The communication device 300 is mounted within a range of several meters from the wireless device 100 in the vehicle 500. The roadside device 400 is installed outside the vehicle 500 and communicates with the communication device 300 in the second band. The vehicle 500 is traveling, communication occurs between the communication device 300 and the roadside device 400 when the vehicle 500 approaches the roadside device 400, and communication occurs between the communication device 300 when the vehicle 500 leaves the roadside device 400. Communication with the roadside device 400 does not occur. That is, in a situation where communication between the wireless device 100 and the terminal device 200 by the wireless LAN is constantly performed in the vehicle, interference between the wireless LAN and the DSRC/ETC may or may not occur.

FIG. 2 shows the configuration of the wireless device 100. The wireless device 100 includes an antenna 10, a first filter 12, a second filter 14, a controller 18, a communication unit 20, a third filter 30, and a first monitor 32. The communication unit 20 includes a second monitoring unit 34. The antenna 10 is configured to be able to transmit and receive at least a signal in the first band. The antenna 10 is, for example, a patch antenna, but is not limited to this. A known technique may be used for the antenna 10. The first filter 12 is arranged between the antenna 10 and a communication unit 20 described later, and passes a signal in the first band. When the signal in the first band is the transmission signal from the communication unit 20 to the antenna 10, the signal in the first band corresponds to the first signal. On the other hand, when the signal in the first band is a transmission signal from the antenna 10 to the communication unit 20, the signal in the first band is a signal of the first signal or a DSRC/ETC signal (hereinafter, referred to as “second signal”). It corresponds to a part.

3A to 3D show an outline of processing by the wireless device 100. In FIG. 3A, the horizontal axis represents frequency. As illustrated, the first band 600 and the second band 602 are arranged adjacent to each other. Here, as an example, it is assumed that the first band 600 is the W56 frequency band and the second band 602 is the W58 frequency band. Therefore, the second band 602 is arranged on the high frequency side of the first band 600. .. The first signal 620 is shown in the first band 600. The first filter characteristic 610 indicates the characteristic of the first filter 12. For the sake of clarity, the pass band in the first filter characteristic 610 is shown to match the first band 600, but the first signal 620 of the channel on the highest frequency side in the first band 600 is passed. If possible, they may not match and may deviate. Further, a third band 604 different from the first band 600 used by the communication unit 20 is arranged on the low frequency side of the first band 600. The third band 604 is also a band in which the wireless LAN can be used, and is a frequency band of 2.4 GHz, for example. Other description will be given later, and the description will return to FIG.

The communication unit 20 uses the first band 600 to perform wireless LAN communication. That is, the communication unit 20 transmits the first signal 620 or receives the first signal 620 with the terminal device 200 of FIG. 1. Although the communication unit 20 may receive the first signal 620 from a wireless LAN device other than the terminal device 200, here, for the sake of clarity, here, a wireless LAN device other than the terminal device 200 is used. Is omitted. In the wireless LAN, the bandwidth of the first signal 620 is variable such as 20 MHz, 40 MHz, 80 MHz, 160 MHz, etc., but here it is assumed to be 40 MHz, for example. The transmission power of the first signal 620 transmitted from the communication unit 20 is also variable, but here it is assumed to be a constant value.

The communication unit 20 can also perform wireless LAN communication using the third band 604. In particular, the communication unit 20 selects one of the first band 600 and the third band 604 to execute wireless LAN communication. The third filter 30 is arranged between the antenna 10 and the communication unit 20 described later, and passes a signal in the third band 604 (hereinafter, referred to as “third signal”). In FIG. 3A, the third filter characteristic 614 shows the characteristic of the third filter 30. For clarity of explanation, the pass band in the third filter characteristic 614 is shown to match the third band 604, but may not match as long as it includes the third band 604. A third signal 624 is shown in the third band 604 of FIG. Returning to FIG.

In such a configuration, in a basic state where DSRC/ETC communication is not performed, the communication unit 20 uses the first band 600 to transmit or receive the first signal 620. During these processes, the second monitoring unit 34 periodically broadcasts a probe request signal on each channel of the third band 604. That is, the second monitoring unit 34 executes the active scan in the third band 604 during the wireless LAN communication in the first band 600. The communication unit 20 also receives a probe response signal corresponding to the probe request signal transmitted by broadcast. By receiving the probe response signal, it is confirmed that there is a device in the wireless LAN using the third band 604, for example, an access point, which monitors the usage status of the third band 604. Equivalent to that. In addition, the second monitoring unit 34 updates the SSID (Service Set Identifier) for reconnection, the connection channel, and the authentication information at any time by active scanning, and outputs the monitoring result of the usage status including these to the control unit 18. To do.

The second filter 14 is arranged so as to be branched from between the first filter 12 and the antenna 10. The reception signal from the antenna 10 is input to the second filter 14. The second filter 14 has a narrower bandwidth than the first filter 12, and passes a signal in a portion of the first band 600 that is closer to the second band 602. In FIG. 3A, the characteristic of the second filter 14 is shown as a second filter characteristic 612. Here, the highest frequency side of the second filter characteristic 612 is shown to match the highest frequency side of the first band 600 and the first filter characteristic 610, but it is the higher frequency side than these. Good. Returning to FIG.

The first monitoring unit 32 is connected to the second filter 14 and receives the signal output from the second filter 14. In particular, the first monitoring unit 32 receives a signal at the timing when the communication unit 20 is not transmitting the first signal 620 or the third signal 624. That is, the first monitoring unit 32 receives the signal received by the antenna 10. The first monitoring unit 32 monitors the usage status of the second band 602 based on the signal output from the second filter 14. To specifically explain this process, FIGS. 3A to 3B are used here. In FIG. 3A, the first signal 620 exists in the first band 600, but the signal does not exist in the second band 602. That is, FIG. 3A shows a basic state in which DSRC/ETC communication is not performed. In this case, since the signal output from the second filter 14, that is, the signal included in the second filter characteristic 612 is about noise, the signal level thereof is generally low. Here, the signal level is indicated by the power of the signal, for example.

On the other hand, in FIG. 3B, the second signal 622 exists in the second band 602. That is, FIG. 3B shows a state in which DSRC/ETC communication is performed and interference may occur. In this case, since the signal output from the second filter 14, that is, the signal included in the second filter characteristic 612 is the leaked component of the second signal 622, the signal level becomes about the leaked power, which is lower than the noise level. growing. Returning to FIG. That is, the first monitoring unit 32 calculates the level of the signal output from the second filter 14, and if the signal level is lower than the threshold value, determines that the second band 602 is unused. On the other hand, the first monitoring unit 32 determines that the second band 602 is being used if the signal level is equal to or higher than the threshold value. This means that the usage status of the second band 602 is monitored by utilizing the leaked component of the second signal 622 of the second band 602. The first monitoring unit 32 outputs the determination result to the control unit 18.

The control unit 18 receives the determination result from the first monitoring unit 32, and controls the setting for communication in the communication unit 20 based on the determination result. The setting for communication in the communication unit 20 is, for example, whether to use the first band 600 or the third band 604. When the usage status, which is the determination result of the first monitoring unit 32, is unused, the control unit 18 sets the first band 600 as described above.

On the other hand, when the usage status monitored by the first monitoring unit 32 changes from unused to usage, the control unit 18 confirms the usage status monitored by the second monitoring unit 34. The control unit 18 selects a channel that is not used in the usage status of the third band 604, that is, a channel that has not received the probe response signal. When all the channels are used, the control unit 18 does not have to select the channel, or may select the channel having a small number of received probe response signals. When a channel is selected, the control unit 18 causes the communication unit 20 to change from using the first band 600 to using the selected channel in the third band 604. This corresponds to connecting to a channel in the third band 604 with less traffic. The result of such control is shown in FIG. The transmission of the first signal 620 in the first band 600 is stopped, and instead the third signal 624 is transmitted in the third band 604.

In this way, the communication unit 20 uses the third band 604 to transmit and receive the third signal 624. During these processes, the second monitoring unit 34 periodically broadcasts a probe request signal on each channel of the first band 600. That is, the second monitoring unit 34 executes the active scan in the first band 600 during the wireless LAN communication in the third band 604. The communication unit 20 also receives a probe response signal corresponding to the probe request signal transmitted by broadcast. By receiving the probe response signal, it is confirmed that there is a device in the wireless LAN using the first band 600, for example, an access point, which monitors the use status of the first band 600. Equivalent to that. Further, the second monitoring unit 34 updates the SSID for reconnection, the connection channel, and the authentication information as needed by active scanning, and outputs the monitoring result of the usage status including these to the control unit 18.

Even while the communication unit 20 is using the third band 604, the first monitoring unit 32 monitors the usage status of the second band 602 based on the signal output from the second filter 14. FIG. 3D shows a case where the usage status of the second band 602 is changed to non-use. The control unit 18 confirms the usage status monitored by the second monitoring unit 34 when the usage status monitored by the first monitoring unit 32 changes from used to unused. The control unit 18 selects a channel that is not used in the usage status of the first band 600, that is, a channel that has not received the probe response signal. When all channels are used, the control unit 18 does not have to select a channel, and may select a channel for which a small number of probe response signals have been received. When the channel is selected, the control unit 18 causes the communication unit 20 to change from using the third band 604 to using the selected channel in the first band 600. This corresponds to connecting to a channel in the first band 600 with less traffic.

In terms of hardware, this configuration can be realized by a CPU, memory, or other LSI of an arbitrary computer, and in terms of software, it can be realized by a program loaded in the memory, but here it is realized by cooperation of them. It depicts the functional blocks that will be used. Therefore, it will be understood by those skilled in the art that these functional blocks can be realized in various forms by only hardware, only software, or a combination thereof.

The operation of the wireless device 100 having the above configuration will be described. FIG. 4 is a flowchart showing a processing procedure by the wireless device 100. The first monitoring unit 32 monitors the usage status of the second band 602 (S10). When the communication unit 20 is using the first band 600 (Y in S12) and the usage status of the second band 602 is in use (Y in S14), the control unit 18 moves to the third band 604. (S16). If the second band 602 is not in use (N in S14), step 16 is skipped. When the communication unit 20 is not using the first band 600 (N in S12), that is, when the third band 604 is in use, the usage status of the second band 602 is not in use (N in S18). The control unit 18 moves it to the first band 600 (S20). If the usage status of the second band 602 is in use (Y in S18), step 20 is skipped.

According to this embodiment, the usage status of the second band used for DSRC/ETC different from the wireless LAN is monitored, and when the usage status changes from unused to usage, the usage status of the third band is also monitored. Moreover, since the use of the first band is changed to the use of the third band, it is possible to reduce the influence on the DSRC/ETC. When the usage status of the second band changes from usage to unused, the usage status of the first band is used to change the usage status of the third band to the usage of the first band. If the influence is small, the first band can be used. In addition, since the second band has a narrower bandwidth than the first filter and the output from the second filter that passes the signal of the part of the first band that is closer to the second band is used, the usage status of the second band is monitored. , The usage status of the second band can be estimated in the device.

Further, since the occurrence of interference is suppressed, it is possible to install the wireless device and the communication device without separating them even in a narrow space inside the vehicle. Further, since the setting in the wireless LAN is changed, stable DSRC/ETC short-range communication system for traffic vehicles can be secured without changing existing DSRC/ETC short-range communication system for traffic vehicles. In addition, since the surrounding environment is always checked by the probe request signal for the frequency band other than the connection while running, the desired frequency is immediately detected even when the DSRC/ETC is detected even under the radio environment that changes variously by running. You can reconnect the wireless LAN with the band.

(Example 2)
Next, a second embodiment will be described. The second embodiment relates to the wireless device of the wireless LAN as in the first embodiment. In the first embodiment, the usage status of the second band is monitored based on the signal output from the second filter. In the second embodiment, the usage status of the second band is monitored by a configuration different from that of the first embodiment. The vehicle 500 in the second embodiment is of the same type as that in FIG. Here, the difference from the first embodiment will be mainly described.

FIG. 5 illustrates the configuration of the wireless device 100 according to the second embodiment. The wireless device 100 includes an antenna 10, a first filter 12, a control unit 18, a communication unit 20, an input unit 22, a third filter 30, and a first monitoring unit 32. The communication unit 20 also includes a second monitoring unit 34. The input unit 22 is connected to the communication device 300 by wire or wirelessly. When executing communication by DSRC/ETC, the communication device 300 outputs a signal indicating the communication to the input unit 22. This signal can be said to be a signal indicating the use of the second band 602.

The first monitoring unit 32 monitors the usage status of the second band 602 based on the signal received by the input unit 22. That is, the first monitoring unit 32 determines that the second band 602 is unused if the input unit 22 does not receive a signal. On the other hand, the first monitoring unit 32 determines that the second band 602 is used if the input unit 22 receives the signal. The signal received by the input unit 22 includes information indicating whether the second band 602 is used or not used, and the first monitoring unit 32 may make a determination based on the information. .. The first monitoring unit 32 outputs the determination result to the control unit 18.

According to this embodiment, since the usage status of the second band is monitored based on the signal from the communication device, the usage status recognition accuracy can be improved.

The present invention has been described above based on the embodiments. It should be understood by those skilled in the art that this embodiment is an exemplification, and that various modifications can be made to the combinations of the respective constituent elements and the respective processing processes, and that such modifications are within the scope of the present invention. ..

In the first and second embodiments, the wireless device 100 includes the control unit 18, the first monitoring unit 32, and the second monitoring unit 34. However, not limited to this, for example, the terminal device 200 is configured to include the control unit 18, the first monitoring unit 32, and the second monitoring unit 34 similarly to the wireless device 100, and executes the same processing as the wireless device 100. You may. According to this modification, the applicable range of the first and second embodiments can be expanded.

In the first and second embodiments, the first band 600 is used for the wireless LAN and the second band 602 is used for the DSRC/ETC. However, not limited to this, for example, the first band 600 and the second band 602 may be used in a communication system other than the wireless LAN and the DSRC/ETC. According to this modification, the applicable range of the first and second embodiments can be expanded.

10 antenna, 12 1st filter, 14 2nd filter, 18 control part, 20 communication part, 30 3rd filter, 32 1st monitoring part, 34 2nd monitoring part, 100 Radio equipment.

Claims (6)

A wireless device in a first communication system using a first band, comprising:
A communication unit that performs communication using the first band,
A second band different from the first band used by the communication unit and a second band used in a second communication system different from the first communication system using the first band is used. A first monitoring unit for monitoring,
A second band that is different from the first band used by the communication unit and that monitors the usage status of the third band or the first band that is usable by the first communication system that uses the first band. Monitoring section,
When the usage status monitored by the first monitoring unit changes from unused to usage, the first band is sent to the communication unit based on the usage status of the third band monitored by the second monitoring unit. A control unit for changing from the use of to the use of the third band,
A wireless device comprising: When the usage status monitored by the first monitoring unit changes from used to unused, the control unit notifies the communication unit based on the usage status of the first band monitored by the second monitoring unit. The wireless device according to claim 1, wherein the use of the third band is changed to the use of the first band. The wireless device according to claim 1 or 2, wherein the first band and the second band are adjacent to each other. A first filter which is arranged between the communication unit and the antenna and which passes a signal in a first band;
A second filter that is arranged so as to be branched from between the first filter and the antenna, has a narrower bandwidth than the first filter, and passes a signal in a portion of the first band near the second band. And further,
4. The wireless device according to claim 1, wherein the first monitoring unit monitors the usage status of the second band based on the output from the second filter. The wireless device according to claim 4, wherein the monitoring unit monitors the usage status of the second band by using the leaked component of the signal of the second band. A signal from a communication device of a second communication system using the second band, the input unit for inputting a signal indicating use of the second band,
The wireless device according to claim 1, wherein the first monitoring unit monitors the usage status of the second band based on the signal input to the input unit.

Images