JP3821271B2 - Wireless communication system for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wireless communication system for a vehicle, and in particular, a helmet is equipped with a wireless communication device and performs wireless communication with a wireless communication device mounted on another helmet via a relay device mounted on the vehicle. The present invention relates to a vehicle radio communication system. The present invention also relates to a radio communication system for vehicles that eliminates the need for a communication line between a transmission unit and a reception unit (that is, between nodes), reduces the weight of the equipment, reduces the cost, and improves the convenience for the user.
[0002]
[Prior art]
In order to enable conversation between passengers riding in a motorcycle, a helmet is equipped with a wireless communication device including a speaker, a microphone and a transceiver on each person's helmet, and a communication system in which wireless communication devices communicate directly with each other. For example, it is disclosed in the microfilm of Japanese Utility Model Laid-Open No. 62-155535.
[0003]
Further, for example, in Japanese Patent Publication No. 7-22431, etc., in a multiplex communication system used for a vehicle such as a motorcycle, a plurality of nodes are connected by a single signal line, and the single signal line is connected. It is described that signals are transmitted / received between both nodes via the.
[0004]
[Problems to be solved by the invention]
A large output signal is required to enable communication by the wireless communication device installed in the helmet not only between the driver and the passenger as described above but also with the passenger of another vehicle. The Therefore, in order to realize this requirement, it is necessary to increase the size of the drive circuit and the battery, or to add a power saving circuit or the like for reducing the power consumption to the wireless communication device equipped in the helmet. However, there has been a problem that the apparatus becomes large.
[0005]
Moreover, in the system described in the above Japanese Patent Publication No. 7-22431, the vehicle body and the helmet are connected by a single signal line. Therefore, whenever the driver gets on and off the vehicle, the vehicle body or the helmet is connected. Therefore, there is a problem that it is necessary to remove the signal line from the cable and the handling is troublesome. As the number of systems increases, this detachment work increases by the number of systems, which increases bothersomeness.
[0006]
The object of the present invention is to solve the above-mentioned problems of the prior art, without increasing the size of the transceiver mounted on the helmet, and with low power consumption, not only between passengers but also with passengers of other vehicles Another object of the present invention is to provide a vehicular wireless communication system that can communicate with each other. Another object is to provide a vehicular wireless communication system that is highly convenient and can be manufactured at low cost.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a wireless communication device that is mounted on each helmet worn by a vehicle occupant and includes at least a speaker, a microphone, and a radio wave transmitter / receiver, and is mounted on a vehicle side. The wireless communication device is equipped with a relay device that wirelessly communicates with the mobile transceiver, and the wireless communication device mounted on each helmet communicates with each other via the relay device.
[0008]
According to the above-described feature, the wireless communication device attached to each helmet always transmits to the relay device regardless of the position of the wireless communication device of the communication partner, so the transceiver of the wireless communication device is connected to the relay device. It is only necessary to provide the minimum transmission capability necessary for close-range communication, and it is possible to reduce the size and weight of the transceiver and reduce the power consumption.
[0009]
According to the present invention, in the vehicular radio communication system that performs communication between a plurality of nodes, at least two of the plurality of nodes include multiplex radio communication means, and multiplex radio communication is performed between the nodes. The point is another feature.
[0010]
According to this feature, it is not necessary to connect a plurality of nodes with a communication line, the convenience of the user (driver) is improved, the device is lighter, the workability is improved, and the manufacturing cost is reduced. Can be planned.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. 1 and 2 are diagrams schematically showing a communication method using a vehicular wireless communication system to which the present invention is applied. Here, communication between four occupants who are divided into two vehicles is performed. An example will be described.
[0012]
A helmet 70 worn by each occupant is equipped with a wireless communication device 701 including a microphone 71, a speaker 72, and a radio wave transmitter / receiver 73. The transceiver 73 incorporates a later-described poip antenna with a shortening coil, and the antenna is not exposed to the outside. The transceiver 73 is detachably attached to the rear center of the helmet 70 via a detachable fixing member.
[0013]
Each vehicle 1 is provided with a relay device 74 that wirelessly communicates with each radio wave transmitter / receiver 73. The relay device 74 includes a downverter (not shown), and changes the output voltage (for example, 12V) of the in-vehicle battery 75 to a predetermined drive voltage (for example, 5V) as a drive source.
[0014]
In such a configuration, when the passengers of the same vehicle, that is, the driver and the passenger communicate with each other, as shown in FIG. 1, for example, the driver's voice is detected by the microphone 71 and converted into a voice signal. To the radio wave transmitter / receiver 73. The radio wave transmitter / receiver 73 of the driver communicates with the radio wave transmitter / receiver 73 of the passenger via the relay device 74 of the own vehicle.
[0015]
When passengers of different vehicles communicate with each other, as shown in FIG. 2, for example, radio waves transmitted from the radio wave transmitter / receiver 73A of the driver of the vehicle 1A are received by the relay device 74A of the own vehicle, Is amplified and retransmitted. The radio wave transmitted from the relay device 74A is received by the passenger's radio wave transmitter / receiver 73A, and simultaneously received by the radio wave transmitter / receiver 73B of the driver of the vehicle 1B and the passenger, and reproduced by the speaker 72B. .
[0016]
The radio wave transmitted from the radio wave transmitter / receiver 73B of the driver of the vehicle 1B is received by the relay device 74B of the own vehicle, amplified here, and retransmitted. The radio wave transmitted from the relay device 74B is received by the passenger's radio wave transmitter / receiver 73B, and simultaneously received by the radio wave transmitter / receiver 73A of the driver and the passenger of the vehicle 1A, and reproduced by the speaker 72A. .
[0017]
FIG. 3 is a transparent perspective view of the transceiver 73, and FIG. 4 is a transparent front view showing the internal structure thereof.
[0018]
The transceiver 73 includes a circuit board 806, an AA battery 804, and a pope antenna 802 with a shortening coil in a rectangular resin case 804, and the circuit board 806 and the AA battery 804 having a relatively large mass are In consideration of the weight balance when the transmitter / receiver 73 is attached to the center of the rear portion of the helmet 70, the transmitter / receiver 73 is distributed to the left and right in the resin case 804. The shortened coiled popip antenna 802 is accommodated so as to crawl along the inside of the resin case 804.
[0019]
On the circuit board 806, a seesaw switch 807 and a power switch 808 for adjusting the volume are mounted together with various circuit elements. The operation buttons 801 and 805 of the switches 807 and 808 are arranged at the center of the rear part of the helmet 70. It is exposed on the left side of the surface located in front of the back when mounted on.
[0020]
As described above, in this embodiment, the circuit board 806 and the AA battery 804 having a relatively large mass are arranged on the left and right sides in the resin case 804, so that the transceiver 73 is attached to the center of the rear part of the helmet 70. However, the weight balance of the entire helmet is maintained, so that the wearing feeling of the helmet is not deteriorated or handling becomes difficult.
[0021]
In addition, since the switch operation buttons 801 and 805 are provided on the rear surface located at the rear front when the transceiver 73 is mounted in the center of the rear part of the helmet 70, the operation buttons 801 and 805 can be easily and accurately operated with either the left or right hand. Further, since the operation buttons 801 and 805 are provided on the left side facing the back, the operation with the left hand is particularly easy, and the operation can be performed without releasing the hand from the throttle grip during driving.
[0022]
FIG. 5 is a block diagram of an embodiment of the above-described vehicle wireless communication system, and the same reference numerals as those described above represent the same or equivalent parts.
[0023]
The transceiver 73 of the wireless communication device 701 equipped in the helmet includes an amplifier 731 that amplifies the audio signal detected by the microphone 71, and transmits the amplified audio signal from the transmission channel T1. In addition, an amplifier 732 that amplifies the audio signal received by the reception channel R 1 is provided, and the amplified audio signal is output from the speaker 72. The amplification factor of the amplifier 732 is controlled by the volume control unit 733.
[0024]
In the relay device 74, the transmission / reception unit 741 includes a first reception channel R1, a second reception channel R2, a first transmission channel T1, and a second transmission channel T2. The first and second reception channels R1 and R2 receive audio signals transmitted from the respective transceivers 73. The first transmission channel T1 transmits an audio signal to each transceiver 73. The second transmission channel T2 transmits a control signal to each transceiver 73.
[0025]
The mixing unit 742 combines and outputs the audio signals received by the first and second reception channels R1 and R2 of the transmission / reception unit 741. The mixing / mute unit 743 mixes audio signals transmitted from the mixing unit 742, the mobile phone 81, another wireless device 82, a music playback device 83 such as a radio, MD, CD, etc., an audio board 84, etc. To the first transmission channel T1 of the unit 741. If the vehicle is equipped with the navigation system 86 as in the present embodiment, the audio signal sent from the navigation system 86 is also mixed. The sound board 84 converts the current time, gear position, turn signal status, etc. into sound signals and outputs them.
[0026]
The mixing / mute unit 743 has a mute function. As will be described in detail later, the mixing / mute unit 743 is prioritized when a high-priority sound source (for example, the telephone 81) competes with a low sound source (for example, the music playback device 83). Attenuate or cut off (mute) the signal transmitted from a sound source with a lower rank.
[0027]
The controller 744 generates a control signal in response to an operation of a switch provided on the operation panel 85 described later, and provides the control signal to the second transmission channel T2 of the mixing / mute unit 743 or the transmission / reception unit 741. The operation panel 85 is provided with a volume adjustment switch 851, a mute switch 852, a PTT switch 853, and a telephone / wireless changeover switch 854.
[0028]
FIG. 6 is a diagram showing the operation of the mixing / mute unit 743 in a table format. When the volume adjustment switch 851 is operated, the controller 744 generates a volume increase / decrease signal in response to this operation. To send. The transmission / reception unit 741 transmits this volume increase / decrease signal from the second transmission channel T2. The volume increase / decrease signal is received by the second reception channel R2 of the transceiver 73 of each wireless communication device 701 and input to each volume control unit 733. The volume control unit 733 controls the amplification factor of the amplifier 732 in response to the received volume increase / decrease signal.
[0029]
When the mute switch 852 is operated, in response to this, the controller 744 generates a mute signal and sends it to the mixing / mute unit 743. The mixing / mute unit 743 attenuates (or cuts off) the output signals of the music playback device 83, the audio board 84, and the mixer 742, and outputs the output signals of the telephone 81 and the radio 82 as they are.
[0030]
When the PTT switch 853 is turned on while the telephone / wireless changeover switch 854 is switched to the telephone side, the output signals of the wireless device 82, the music playback device 83, and the audio board 84 are transmitted by the mixing / mute unit 743. Attenuated. If the PTT switch is pressed while the telephone / wireless switch is switched to the wireless side, the output signals of the telephone 81, the music player 83 and the voice board 84 are similarly attenuated.
[0031]
FIG. 8 is a side view of the motorcycle on which the relay device 74 of the above-described vehicle wireless communication system is mounted, and FIG. 9 is a perspective view of the main part. A scooter type motorcycle (hereinafter referred to as “vehicle”) 1 has a double cradle type body frame 2 extending in the front-rear direction of the vehicle body. A head pipe 3 is attached to the front end of the vehicle body frame 2, and a front wheel 5 is attached to the tip of a front fork 4 that extends downward from the head pipe 3. The front wheel 5 is covered with a front fender 6 at the top. A handle 7 is fixed to the upper portion of the front fork 4, and the front and rear of the handle 7 are covered with a handle cover 33 that is divided into two front and rear.
[0032]
The handle bar 33 is provided with a transparent wind screen 34 via a stay (not shown), and a screen garnish 35 as a cover member is provided at the lower front portion of the wind screen 34. The relay device 74 is installed on the back of the instrument panel inside the screen garnish 35. The handle cover 33 is provided with a PDA storage box (hereinafter simply referred to as “box”) 100 capable of storing a PDA (details will be described later) used for the navigation system. The box 100 is pivotally supported so as to be swingable in the direction of the arrow NA.
[0033]
A fuel tank 8, a radiator reserve tank 9, and a radiator 10 are provided in a cradle space surrounded by each pipe of the body frame 2, and a power unit 12 having a water-cooled engine 11 at the front is provided behind the cradle space. Is provided. The power unit 12 is swingably attached to the vehicle body frame 2 with its front portion suspended by a link mechanism 13 and its rear end portion suspended by a rear cushion 14. A rear wheel 15 is attached to the rear portion of the power unit 12, the vehicle body frame 2 is covered with a body cover 17, and a seat 16 is disposed on the rear upper portion of the vehicle body frame 2.
[0034]
The body cover 17 forms a front portion with a front cover 21 that covers the front portion of the head pipe 3 and the top of the front wheel 5 and an inner cover 22 that covers the rear portion of the front cover 21. The left and right step floors 23 on which the driver puts his / her feet extend rearward from the inner cover 22, and the floor skirt 24 extends downward from the outer edge of the step floor 23. The lower edge of the floor skirt 24 is covered with an under cover 25, and the longitudinal center of the body frame 2 is covered with a center cover 26 extending rearward from the inner cover 22. Both side surfaces of the rear part of the body frame 2 are covered with side covers 27 extending rearward from the center cover 26.
[0035]
The left and right lower side covers 28 extend downward from the outer edge of the side cover 27, and the rear lower portion of the vehicle body frame 2 is covered with a rear center cover 29 provided behind the lower side cover 28. A rear upper end portion of the vehicle body frame 2 is covered with a rear upper cover 30 provided above the rear center cover 29.
[0036]
A headlamp 41 and a blinker light 42 are mounted on the front cover 21. Further, a GPS sensor 110 that receives GPS satellite radio waves for the navigation system and outputs positioning data and an MPU 111 as a system controller that controls the navigation system are disposed on the front cover 21. The GPS sensor 110 is not limited to the front part of the vehicle body but may be mounted (reference numeral 110a) on the rear part of the vehicle body such as the rear upper cover 30 or the like. The screen garnish 35 is provided with air guide holes 35a, 35a, and traveling wind along the front surface of the front cover 21 flows upward and is guided to the air guide holes 35a, 35a.
[0037]
A part of the center cover 26 is provided with an oil supply lid 43 and a spark plug inspection lid 44. A main stand 45 is provided at the lower part of the vehicle body, and an air cleaner 46 is provided inside the lower side cover 28. Further, a rear grip 47, a tail lamp 48, and a rear fender 49 are provided at the rear part of the vehicle body.
[0038]
Next, a second embodiment of the communication system of the present invention that communicates between occupants of the same vehicle or between occupants of different vehicles will be described. FIG. 25 is a block diagram showing a schematic configuration of the embodiment.
[0039]
The rider side unit 301 attached to the helmet of the driver or the like and the vehicle body side unit 302 attached to the vehicle body each include a wireless communication device having a well-known Bluetooth standard. The vehicle body side unit 302 includes an ETC unit 303 for an automatic toll collection system, a GPS receiving unit 304 for a navigation device, a Mayday unit 305, an electronic notebook (PDA) 6, communication with other vehicles, or communication with other vehicles. An SS modem 307 used for detecting the distance, various acoustic sources 308 for stereo, and the like are connected by wire. Note that this wire may be wireless using a Bluetooth standard multiple connection function as necessary.
[0040]
Next, a specific configuration example of the rider side unit 301 will be described with reference to FIG. A microphone 312 is disposed at the mouth portion of the helmet 311 such as a driver, and a speaker 313 is disposed at the ear portion. Further, an antenna 314 is provided at an appropriate position of the helmet 311. The microphone 312, the speaker 313, and the antenna 314 are schematically shown.
[0041]
The antenna 314 is connected to an RFIC 316 that functions as a communication device via a bandpass filter 315. The RFIC 316 has a reception side path and a transmission side path, and these are switched by the antenna SW 316a. The reception side path is composed of a low noise amplifier LNA, a mixer IRM, an IF band pass filter IFBPF, a limit amplifier LIMAMP, a demodulator DEM, and a low pass filter LPF. On the other hand, the transmission side circuit is composed of a Gaussian filter, a switch SW, a PLL circuit, an LPF, voltage controlled oscillators VCO and SW, and a power amplifier PA.
[0042]
A baseband IC 317 that is a baseband signal processing device includes a baseband controller, a ROM, a RAM, a CPU, a PCM / CVSD transcoder, an external bus I / F, a device controller, and a power supply voltage, each connected to a bus. It comprises a voltage regulator that stabilizes the power supply and a power management unit PMU.
[0043]
The sound picked up by the microphone 312 is amplified by the power amplifier 318 and connected to the input / output I / F 320. On the other hand, the received audio signal sent from the input / output I / F 320 is amplified by the power amplifier 319, reaches the speaker 313, and is reproduced as audio. A main SW 322 is connected to the SWI / F 321.
[0044]
Note that the RFIC 316 and the baseband IC 317 are well-known circuits, and a detailed description of the operation is omitted. 26 is preferably built in a resin case 804 attached to the back of the helmet 311 (see FIG. 3).
[0045]
Next, a specific configuration example of the vehicle body side unit 302 will be described with reference to FIG. The vehicle body side unit 302 includes an antenna 325, a bandpass filter 326, an RFIC 316 having the same configuration as that shown in FIG. 26, a baseband IC 317, and an external device connection IC 327. The external device connection IC 327 includes a ROM, a RAM, a CPU, an external control I / F, a voice synthesis LSI, a voice recognition LSI, a sensor I / F, and an audio I / F, each connected to a bus. ing. The ETC unit 303, GPS receiving unit 304, Mayday unit 305, PDA 306, and SS modem 307 are connected to the external control I / F, and a mobile phone is connected as necessary. Various audio sources 308 are connected to the audio I / F. Further, a hand operation SW 331 and various sensors 332 (a vehicle speed sensor, a tilt sensor, etc.) are connected to the sensor I / F. The hand operation SW 331 includes a mute SW 331a, a volume SW 331b, and a PTT (Push To Talk) SW 331c, as shown in FIG.
[0046]
Since this embodiment is configured as described above, the driver does not need to connect the rider side unit 301 and the vehicle body side unit 302 with a communication line, in other words, the helmet 311 and the vehicle body side unit 302. Even if the communication line is not connected, the vehicle can be driven wirelessly, for example, by receiving music signals reproduced by various acoustic sources 308 and listening to music. The volume at that time can be adjusted by the volume SW 331b. In addition, the driver can perform communication (conversation) with other vehicles wirelessly from the rider side unit 301 directly or via the vehicle body side unit 302.
[0047]
In addition, it is preferable that communication between the rider side unit 301 and the vehicle body side unit 302 is performed by multiplex wireless communication (for example, code division multiplex CDMA or time division multiplex communication TDMA). FIG. 29 is a timing chart showing an example of the multiplex wireless communication. The master communicates with the slaves 1 to 3 in a time-sharing manner in a time slot having a period of time t1 to t2. As a result, the master can communicate with the slaves 1 to 3 in parallel.
[0048]
For example, if the rider side unit 301 is the master, the SS modem 307 on the vehicle body side unit 302 side, and the various sound sources 308 are the slaves and multiplex wireless communication is performed, for example, while driving the vehicle while listening to music, When there is a possibility of abnormal approach, the signal from the SS modem 307 can be immediately transmitted to the driver, and the driver can avoid danger.
[0049]
Therefore, according to the present embodiment, since a communication line is not required between the helmet 311 and the vehicle body side unit 302, work such as wiring, connection, or extension of the communication line, or a member necessary for it is unnecessary. It becomes possible to reduce the weight of the apparatus, improve workability, and reduce manufacturing costs. In addition, when the driver leaves the vehicle while wearing a helmet, it is not necessary to remove the communication line from the helmet or to attach the communication line to the helmet when getting on the vehicle. Is greatly improved. Further, by adopting Bluetooth standard devices for the rider side unit 301 and the vehicle body side unit 302, a communication device can be constructed at low cost, and short-distance wireless data communication (maximum transmission distance is 10 m). Effective use of resources becomes possible. It is also effective in parking lots and traffic jams.
[0050]
In the present embodiment, since the helmet 311 and the vehicle body side unit 302 communicate with each other wirelessly, compared to a system that communicates between both using infrared rays, it is possible to prevent disturbance due to directivity, sunlight, or the like. There are few restrictions and it is very advantageous.
[0051]
Next, a third embodiment of the communication system according to the present invention will be described with reference to FIG. This embodiment is characterized in that external communication means such as a mobile phone with built-in Bluetooth module 341, PHS, etc. is added to the system of the second embodiment. The Bluetooth module built-in mobile phone 341 may be connected to only one of the rider side unit 301 and the vehicle body side unit 302 by a communication line, or may be completely independent without being wiredly connected thereto. . The mobile phone 341 with built-in Bluetooth module is put in a pocket of a driver's clothes and can be accompanied by the driver, but it can be put in a tank bag attached to the vehicle or hidden from the appearance on the vehicle body. It may be attached and fixed to the part so that it cannot be accompanied by the driver.
[0052]
In this embodiment, the driver accesses the mobile phone 341 with built-in Bluetooth module from the rider side unit 301 of the helmet and communicates via the mobile phone 341, thereby enabling communication with an external person located far away. . The vehicle body side unit 302 can access the Bluetooth module built-in mobile phone 341 and communicate with the outside via this.
[0053]
For example, when an automatic accident reporting device is mounted on a vehicle, it is detected that the vehicle has encountered a traffic accident by detection signals from a vehicle speed sensor, an inclination sensor, etc. in the various sensors 332. Then, the telephone number of the accident reporting center registered in advance is automatically read out by the functions of the CPU, ROM, RAM, etc. of the baseband IC 317 in the vehicle body side unit 302, and the data of the telephone number is built into the Bluetooth module. It is sent to the mobile phone 341 by radio or wire. Then, the mobile phone with built-in Bluetooth module 341 automatically calls the telephone number and notifies the accident reporting center that an accident has been encountered. As a result, for example, even if you are driving alone on a motorcycle, even if you encounter an accident and lose consciousness, this accident will be automatically reported to the accident reporting center, and the driver will receive emergency relief. Will be able to. When there is no need to report to the accident reporting center due to a light fall or the like, a means for stopping the reporting is provided (not shown).
[0054]
According to this embodiment, when the driver is in the vehicle, communication between the driver and the outside and communication between the vehicle and the outside are possible as long as the driver is in the vicinity of the vehicle even when getting off the vehicle. . Therefore, regardless of whether the driver is in the vehicle, the communication means to the outside, that is, the mobile phone with built-in Bluetooth module 341 can be shared by the driver and the vehicle.
[0055]
Further, when the mobile phone 341 with built-in Bluetooth module is made independent of both the rider-side unit 301 and the vehicle body-side unit 302, when the driver gets off, the helmet is removed and fixed to the vehicle, and the Bluetooth module is built-in. When only the mobile phone 341 is carried away from the vehicle, the communication line is not required to be attached or detached, and convenience is improved. On the contrary, from this state, when the user gets on the vehicle, the installation work of the communication line is unnecessary, and the convenience is improved.
[0056]
Next, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment is characterized in that a rider side unit 301a is also attached to the passenger's helmet 311a so that the passenger and the driver, and between the passenger and the vehicle body side unit can communicate wirelessly. The passenger may be a driver of a vehicle that runs side by side.
[0057]
According to this embodiment, the communication line between the driver and the passenger is not necessary, and both are not bound to each other by the communication line when getting off the vehicle. Further, it is not necessary for the passenger to remove the communication line from the helmet when the helmet is attached or detached, so that convenience is improved and information from the vehicle body side unit 302 can be received. In addition, when the helmet 311a is a driver of a vehicle running side by side, when the vehicle is waiting for a signal at an intersection, the two vehicles must be adjacent to each other without raising a loud voice over the helmet. However, for example, if the distance is within 10 m, a wireless call can be made with a normal voice without being adjacent to each other.
[0058]
Next, a fifth embodiment of the communication system of the present invention will be described. In this embodiment, for example, in FIG. 25, the wireless communication is divided into full-duplex and others, for example, full-duplex and half-duplex, and high-priority information is full-duplex. Low information is characterized by other things, for example, full or half duplex.
[0059]
For example, in FIG. 25, the communication between the lidar unit 301 and various acoustic sources is half-duplex, and the communication with, for example, the SS modem 307 that detects the possibility of abnormal proximity to other obstacles has occurred. Is classified as full-duplex. In this way, the possibility of abnormally approaching the obstacle is transmitted to the driver without delay, and contact and collision with the obstacle can be avoided.
[0060]
Next, a sixth embodiment of the communication system according to the present invention will be described with reference to FIG. This embodiment includes a Bluetooth standard wireless communication device when the driver of the vehicle 1A wearing the helmet 311 and the driver of the vehicle 1B wearing the helmet 311b are within a short distance of, for example, 10 m or less. The communication between the units 301 and 301b is characterized in that communication can be performed via the relay devices 74A and 74B having high power when they are separated by a long distance (for example, 10 m or more).
[0061]
Specifically, when the intensity of the received radio wave is detected by the baseband controller of the baseband IC 317 in FIG. 26 showing the specific configuration of the units 301 and 301b and the received radio wave intensity falls below a predetermined threshold value. The settings such as the communication path may be changed so that the units 301 and 301b communicate via the relay devices 74A and 74B.
[0062]
According to this embodiment, there is an advantage that the radio wave resource can be effectively used and communication can be continued without interruption even if it is several tens of meters away.
[0063]
FIG. 10 is a system configuration diagram of the navigation system. The GPS sensor 110 and the PDA 200 accommodated in the box 100 are connected to the MPU 111 as a system controller that centrally manages navigation operations. The PDA is known as a personal form information device having a function of managing a personal schedule, a display panel function capable of pen input, a function of searching and storing a large amount of information such as a dictionary and a manual, In this embodiment, these functions can be used as a navigation function by storing or retrieving map information. The box 100 is also provided with a switch 102 for switching and scrolling the display screen of the PDA 200 and reducing / enlarging the map. This switch 102 is also connected to the MPU 111. The power source of the MPU 111 is taken from an in-vehicle battery 112. Although the PDA 200 has a battery inside, when connected to the MPU 111 and used, the PDA 200 can receive power from the battery 112 via the MPU 111.
[0064]
The PDA 200 has a memory capable of storing travel data and a display screen, and provides navigation information according to positioning data from the GPS sensor 110 and a control signal from the MPU 111 to perform a navigation operation. The travel data includes electronic map information and route information to the destination. The travel data is created based on information obtained from a network such as the Internet using a personal computer and electronic map information, for example. A travel route is created by giving a destination as input information, and waypoints such as main intersections on the route are selected according to a preset algorithm when the route is determined. The travel data may be input from a personal computer, or information stored in advance in a ROM or the like may be transferred.
[0065]
The MPU 111 supplies a control signal c1 to the GPS sensor 110, and the GPS sensor 110 receives GPS satellite radio waves according to the control signal c1. The GPS sensor 110 inputs positioning data d1 based on GPS satellite radio waves to the MPU 111. The MPU 111 analyzes the positioning data d1 and the instruction signal d2 from the switch 102, and supplies the control signal c2 and the positioning data d1 to the PDA 200. The PDA 200 is activated by the control signal c2, uses the positioning data d1, executes a scheduled program, and displays navigation information on the display panel. The PDA 200 inputs a state signal d3 indicating an operation state to the MPU 111.
[0066]
Next, an attachment mode of the box 100 in which the PDA 200 is accommodated will be described. 7 is a front side perspective view of the vehicle to which the box 100 is mounted, FIG. 11 is a front perspective view thereof, and FIG. 12 is a front perspective view showing a state in which the PDA 200 is moved (rotated) to a non-use position. In these figures, the same reference numerals as those in FIG. 8 denote the same parts. In each figure, the wind screen 34 is removed. An instrument panel (meter) 50 is incorporated in the handle cover 33. A speedometer 51 is provided at the center of the surface of the instrument panel 50, a fuel gauge 52 is provided on the left side, and a water temperature gauge 53 is provided on the right side.
[0067]
A hazard switch 54 is provided on the upper front side adjacent to the right side of the instrument panel 50, a start switch 55 is provided on the lower side, and a kill switch 56 is provided on the upper surface. Further, a winker switch 57 is provided on the upper front side adjacent to the left side of the instrument panel 50, a horn switch 58 is provided on the lower side, and the operation panel 85 and the high beam / low beam switch 59 are provided on the upper surface.
[0068]
The box 100 is mounted along the lower edge of the instrument panel 50. The box 100 is sized and shaped to accommodate a PDA having a memory and a display panel that can store map information used in the navigation system. The box 100 is provided with a window 101 and a switch 102 provided with transparent glass or a transparent acrylic sheet so that the display panel of the PDA 200 accommodated therein can be seen. As shown by arrows in FIG. 11, a switch 102 that can be operated left and right and up and down is used. Left and right clicks are used to switch the display panel of the PDA 200, and up and down clicks are used to enlarge and reduce the map. The surface 103 of the box 100 on which the window 101 and the switch 102 are provided is a lid, and the lid 103 is opened to detach the PDA. The lid 103 is provided with a knob 104. By rotating the knob 104, the lid 103 can be locked and unlocked. It is preferable that the knob 104 can be locked and unlocked by an engine key for security.
[0069]
The box 100 has pivot shafts 105 and 105 extending to the left and right, and the pivot shafts 105 and 105 are supported by bearings (not shown) incorporated in the handle cover 33, respectively. When using the navigation system, as shown in FIGS. 7, 8 and 11, the box is moved by a spring means (not shown) to a position (first position) where the display surface of the PDA substantially coincides with the surface of the instrument panel 50. 100 is lifted (popped up). On the other hand, when the navigation system is not used, the box 100 can be pushed down and retracted to a position where the display surface of the PDA, that is, the window 101 is substantially vertical (second position). Locking means such as a magnet catch may be provided on the back surface of the box 100 and the handle cover 33 so that the box 100 is fixed to the handle cover 33 in this retracted position.
[0070]
The rotary shafts 105, 105 are provided with a rotary damper that acts against the spring means when the box 100 is rotated from the retracted position (position in FIG. 12) to the use position (position in FIG. 7). Is good. This is because it is convenient to protect the PDA from the smooth rotation of the box 100 and the vibration of the vehicle and to prevent the display screen from vibration. As the rotary damper, an oil damper in which oil is sealed in a package can be used. This damper action functions only when the box rotates to the first position, and the damper action does not function when the box rotates from the first position to the second position. Therefore, when the user wants to look at the GPS display screen, that is, the display panel of the PDA, the screen can be gently rotated from the retracted position (second position), and when the user wants to retract, the user can quickly retract.
[0071]
FIG. 13 is a perspective view of the box 100 showing a state in which the lid 103 is opened. A relay unit 107 having a multipolar connector 106 coupled to the input / output terminal of the PDA 200 is provided in the box 100. The relay unit 107 relays the signal from the connector 106 to the MPU 111 and relays the signal of the switch 102 to the MPU 111 via the cable 108. The PDA 200 is detachable from the box 100 through the connector 106.
[0072]
Accordingly, the PDA 200 can be connected to the connector 106 and incorporated as a navigation system when the vehicle is in the vehicle, and when the driver leaves the vehicle, the PDA 200 is disconnected from the connector 106 and extracted from the box 100, and is carried independently of the navigation system. be able to. Since the PDA 200 is housed in the box 100 in this way, the PDA 200 can be easily removed from the vehicle, which is advantageous from the viewpoint of theft prevention. Of course, the PDA 200 is not used for navigation but used as an address book or a dictionary. It is also convenient when used as a functional information device. In addition, since the connection portion with the PDA is also accommodated in the box 100, the influence of rain, wind, dust, etc. can be suppressed to a low level.
[0073]
The state transition in the navigation system will be described with reference to the state transition diagram of FIG. 14 and an example of the display screen (FIGS. 15 to 20). In FIG. 14, the status S0 is waiting for data reception. When there is data in the memory of the PDA 200, or when reception of data is completed normally, the process proceeds to status S1. In the status S1, the system further waits for data reception and waits for an activation command. In the statuses S0 and S1, the title screen P1 shown in FIG. 15 is displayed on the display panel.
[0074]
When the switch 102 is left-clicked in the status S1, the status shifts to the status S2. In status S2, an arrow navigation display screen is displayed (see FIG. 16). On the arrow navigation display screen, an arrow N1 and a dot mark N2 indicating the direction of the waypoint, a name N3 of the waypoint, a number N4 indicating the great circle distance to the waypoint, and a decrease in the distance N4 to the waypoint are displayed in a bar graph. A graphic N5 is displayed.
[0075]
When the switch 102 is left-clicked in the status S2, the status shifts to the status S3. In status S3, a frame map navigation screen is displayed (see FIG. 17). On the top map navigation screen, the shape of the waypoint and the arrow N6 in the traveling direction are displayed large, and the direction of the waypoint is displayed as a small arrow N7. When the switch 102 is left-clicked in the status S3, the process proceeds to the status S4. When the switch 102 is right-clicked, the process returns to the status S2. In status S4, a map navigation screen is displayed. In this status S4, the map is fixed.
[0076]
When the switch 102 is left-clicked in the status S4, the process proceeds to the status S5, and when the switch 102 is right-clicked, the process returns to the status S3. In status S5, in addition to the display of status 4, a map navigation screen with a travel locus is displayed (see FIG. 18). The arrow N8 in the figure is the vehicle position and the traveling direction, and the locus is indicated by a dot N9.
[0077]
When the switch 102 is left-clicked in the status S5, the process proceeds to the status S6, and when the switch 102 is right-clicked, the process returns to the status S4. In the status S6, a map navigation screen with only the travel locus is displayed except for the map.
[0078]
When the switch 102 is left-clicked in the status S6, the process proceeds to the status S7, and when the switch 102 is right-clicked, the process returns to the status S5. In the status S7, the map navigation screen is displayed with the vehicle position fixed. Accordingly, a screen on which the map is scrolled according to the traveling of the host vehicle is displayed.
[0079]
When the switch 102 is left-clicked in the status S7, the process proceeds to the status S8, and when the switch 102 is right-clicked, the process returns to the status S6. In the status S8, a map navigation screen with a traveling locus is displayed with the vehicle position fixed.
[0080]
If the switch 102 is left-clicked in the status S8, the process proceeds to the status S9. If the switch 102 is right-clicked, the process returns to the status S7. In the status S9, the map navigation screen with only the traveling locus is displayed except for the map in a state where the vehicle position is fixed.
[0081]
When the switch 102 is left-clicked in the status S9, the process proceeds to the status S10, and when the switch 102 is right-clicked, the process returns to the status S8. In status S10, the arrangement of the satellites is displayed (see FIG. 19). In FIG. 19, a satellite N10 that is in use, a satellite N11 that is on standby, and a satellite N12 that is currently being searched are displayed along with their azimuths.
[0082]
When the switch 102 is left-clicked in the status S10, the process proceeds to the status S11. When the switch 102 is right-clicked, the process returns to the status S9. In the status S11, latitude and longitude indicating the position of the vehicle is displayed (see FIG. 20). This display screen shows the traveling speed, latitude, longitude, and direction of travel of the host vehicle.
[0083]
If the switch 102 is left-clicked in the status S11, the process returns to the status S2. If the switch 102 is right-clicked in the status S2, the status S3 to S10 are skipped and the process proceeds to the status S11.
[0084]
The above state transition diagram shows an example of transition according to the operation of the switch 102, but the arrow navigation display and the frame map navigation display based on the position of the vehicle up to the waypoint regardless of the operation of the switch 102. And can be switched. For example, the arrow navigation display is performed until reaching 400 m before the waypoint, and the arrow navigation display is switched to the frame map navigation display when reaching 400 m before the waypoint. In addition, when the vehicle passes through the waypoint and is 50m away or when it does not go straight at the intersection, and the vehicle body faces the direction of exiting the intersection, the target waypoint is switched and the arrow navigation display is displayed from the top map navigation display. Switching to is performed. Further, the waypoint is automatically updated when it deviates from the set travel route.
[0085]
Subsequently, a modified example will be described. In the above-described embodiment, the box 100 that accommodates the PDA 200 is attached along the lower edge of the instrument panel 50. However, the present invention is not limited to this position, and can be attached, for example, above the instrument panel 50. 21 is a front side view of the vehicle showing the box 100 provided above the instrument panel 50, and FIG. 22 is an enlarged cross-sectional view of the main part of FIG. FIG. 23 is a cross-sectional view when the box 100 is stored.
[0086]
The upper plate 60 forms part of a cover 61 that covers the upper portion of the instrument panel 50, and is supported on the cover 61 by a hinge 62 so as to be rotatable. An upper edge of the box 100 that accommodates the PDA 200 is connected by a hinge 63 to the end of the upper plate 60, that is, the end opposite to the side supported by the hinge 62. Further, at both ends of the lower edge of the box 100, there are provided sliders 65 that are fitted and slid onto a pair of two rails 64 (only one side is shown) provided to be distributed to the left and right of the vehicle body.
[0087]
With this configuration, when the upper plate 60 is lifted from the state in which the box 100 is folded as shown in FIG. 23, the box 100 is coupled to the end of the upper plate 60 by the hinge 63. Can be lifted. On the other hand, the lower edge of the box 100 slides on the rail 64 via the slider 65 and is guided to the end of the rail 64 (near the rear of the vehicle body). Thus, as shown in FIGS. 21 and 22, the box 100 is started up with the display panel surface of the PDA 200 facing the driver, the display surface of the instrument panel 50 and the display panel surface of the PDA are substantially parallel, Is easy to see. 21 and 22, when the upper plate 60 is pushed down while pushing near the lower edge of the box 100 with a finger, the box 100 is in a state where the display panel surface of the PDA 200 faces downward as shown in FIG. It is stored in the cover 61.
[0088]
In the above embodiment, the box 100 opens the lid 103 supported by the hinges to detach the PDA 200, but the structure of the box 100 is not limited to this. FIG. 24 is a perspective view showing a modified example of the box 100. An opening 66 for attaching / detaching the PDA 200 is provided on the end face of the box 100A, and a lid 67 is adapted to the opening 66. The box 100A is provided with a window 101 and a switch 102 through which a display panel of a PDA accommodated therein can be seen, and a connector (not shown) for connecting terminals of the PDA 200, as in the embodiment of FIG.
[0089]
When the PDA 200 is used in a navigation system, the lid 67 is opened, the PDA 200 is inserted into the box 100A through the opening 66, and the lid 67 is fitted into the opening 66 and sealed. When the PDA 200 is not used by being incorporated in the navigation system, the lid 67 is removed and the opening 66 is opened, and the PDA 200 is removed from the box 100A.
[0090]
In addition, it is good to interpose the packing and seal | sticker for waterproof and dust prevention in the fitting surface of the lid | cover 103 of the boxes 100 and 100A demonstrated regarding FIG. 13, FIG. 24, etc., the lid | cover 67, and the boxes 100 and 100A.
[0091]
【The invention's effect】
According to the present invention, the following effects are achieved.
[0092]
(1) Since the wireless communication devices equipped in each occupant's helmet communicate with each other via a relay device mounted on the vehicle, each wireless communication device has the minimum necessary for communication at a short distance with the relay device. It is only necessary to provide a limited transmission capability, and it is possible to reduce the size and weight of the wireless communication device and reduce the power consumption.
[0093]
(2) Since the transmitter / receiver of the wireless communication device is provided at the center of the rear part of the helmet, the wearing feeling of the helmet is not deteriorated or the handling is not difficult.
[0094]
(3) Since the relay device mounted on the vehicle side transmits the audio signal output from the navigation system, the mobile phone or the music playback device such as MD, CD, etc. with the received audio signal, The viewing of audio information sent from the navigation system or the like is not interrupted by the conversation with the passenger.
[0095]
Furthermore, since the voice of the navigation system can be heard not only by the driver and passengers but also by the passengers of other vehicles at the same time, it is preferable that the drivers of each vehicle can share information when touring in multiple vehicles. It is.
[0096]
In addition, if only the voice of the navigation system can be heard regardless of the display, navigation only by voice becomes possible.
[0097]
(4) When mixing and transmitting the received audio signal and the audio signal output from the music playback device, the predetermined audio signal can be selectively attenuated or blocked (muted), so the importance (or An audio signal with high priority is not disturbed by other audio signals with low importance.
[0098]
(5) Since the circuit board and power supply (battery) with a relatively large mass are distributed on the left and right sides of the case, the entire helmet will be installed even if the transceiver is mounted on the rear center of the helmet. The weight balance is maintained.
[0099]
(6) Since the operation buttons of the transmitter / receiver attached to each helmet are provided on a relatively wide surface located in the rear front when the transmitter / receiver is attached to the rear center of the helmet, the operation buttons can be enlarged, It can be operated easily and accurately even while wearing gloves.
[0100]
(7) Since the transceiver antenna is reduced in size and weight and the size of the circuit board is reduced to the size of an AA battery, the use of an AA battery as a power source reduces the dead space in the transceiver and reduces the size. It becomes possible.
[0101]
(8) Wireless communication between multiple nodes eliminates the need to connect communication lines between the nodes, improving convenience for users (drivers, etc.), reducing device weight, and working It is possible to improve the performance and reduce the manufacturing cost.
[0102]
(9) Since the Bluetooth standard device is adopted as the multiplex wireless communication means, the communication device can be configured at low cost, and since it is a short-range wireless data communication (maximum transmission distance is 10m), effective use of radio resources Is possible.
[0103]
(10) Since the node equipped in the helmet worn by the driver and the node mounted on the vehicle are wirelessly communicated, when the driver leaves the vehicle, the communication line is removed from the helmet, On the other hand, since it is not necessary to attach a communication line to the helmet when getting on the vehicle, the convenience for the driver is greatly improved.
[0104]
(11) Since the external communication means that enables communication to the outside of the vehicle is provided, communication between the driver and the outside, and between the vehicle and the outside becomes possible. For this reason, the driver can communicate with a distant person while driving and can also report to the accident reporting center.
[0105]
(12) For example, there is no need for a communication line connecting the motorcycle driver and the rear seat passenger's helmet, so there is no restriction between the two and wireless communication can be enjoyed.
[0106]
(13) For example, information that conveys driving information to the driver is full-duplex, and information that is irrelevant or less related to driving such as music is made half-duplex, so that it is useful information for the driver while ensuring safety. Will be able to provide.
[0107]
(14) By appropriately switching between communication between Bluetooth standard communication devices and communication via a relay device provided in the vehicle, radio resources can be used effectively and communication is interrupted. The trouble can be avoided.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a communication method between passengers by a vehicular wireless communication system to which the present invention is applied.
FIG. 2 is a diagram schematically showing a communication method other than passengers by a vehicular wireless communication system to which the present invention is applied.
FIG. 3 is a transparent perspective view of one embodiment of a transceiver.
FIG. 4 is a transparent front view showing the internal structure of the transceiver.
FIG. 5 is a block diagram of a vehicle radio communication system according to an embodiment of the present invention.
FIG. 6 is a diagram showing the operation of the mixing / mute unit in a table format.
FIG. 7 is a perspective view of an instrument panel turn of a vehicle according to an embodiment of the present invention.
FIG. 8 is a side view of a motorcycle to which the vehicular wireless communication system of the present invention is applied.
FIG. 9 is a front perspective view of the vehicle.
FIG. 10 is a system configuration diagram of a navigation system.
FIG. 11 is a front perspective view showing the periphery of the instrument panel of the vehicle.
FIG. 12 is a perspective view of the main part showing the periphery of the instrument panel of the vehicle.
FIG. 13 is a perspective view of a PDA storage box showing a state in which a lid is opened.
FIG. 14 is a state transition diagram in the navigation system.
FIG. 15 is a diagram showing a display example (1) of the PDA display panel.
FIG. 16 is a diagram showing a display example (2) of the PDA display panel.
FIG. 17 is a diagram showing a display example (3) of the PDA display panel.
FIG. 18 is a diagram showing a display example (4) of the PDA display panel.
FIG. 19 is a diagram showing a display example (5) of the PDA display panel.
FIG. 20 is a diagram showing a display example (6) of the PDA display panel.
FIG. 21 is a front side view showing a box provided above the instrument panel.
22 is an enlarged cross-sectional view of a main part of FIG. 21. FIG.
FIG. 23 is a cross-sectional view of a main part of the vehicle when the box is stored.
FIG. 24 is an exploded perspective view according to a modified example of a box that accommodates a PDA.
FIG. 25 is a block diagram showing a schematic configuration of a second embodiment of the present invention.
FIG. 26 is a block diagram showing a configuration of a specific example of a rider side unit.
FIG. 27 is a block diagram showing a configuration of a specific example of a vehicle body side unit.
FIG. 28 is a circuit diagram showing a specific configuration of the hand operation SW.
FIG. 29 is a timing chart of an example of multiplex wireless communication.
FIG. 30 is a block diagram showing a schematic configuration of a third embodiment of the present invention.
FIG. 31 is a block diagram showing a schematic configuration of a fourth embodiment of the present invention.
FIG. 32 is a diagram schematically showing a schematic configuration of a sixth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Body frame, 33 ... Handle cover, 50 ... Instrument panel, 71 ... Microphone, 72 ... Speaker, 72 ... Helmet, 73 ... Radio wave transmitter / receiver, 74 ... Relay device, 75 ... In-vehicle battery, 100 ... PDA storage box, 101 ... window, 102 ... switch, 103 ... lid, 104 ... knob, 105 ... rotating shaft, 110 ... GPS sensor, 111 ... MPU, 301 ... rider side unit, 302 ... vehicle body side unit, 311 ... helmet , 312 ... microphone, 313 ... speaker, 314 ... antenna, 316 ... RFIC, 317 ... baseband IC, 327 ... external device connection IC, 331 ... hand operation SW, 332 ... various sensors, 341 ... mobile phone with built-in communication device, 701 ... a wireless communication device.

Claims (16)

A wireless communication device mounted on each helmet worn by a vehicle occupant and comprising at least a speaker, a microphone, and a radio wave transceiver,
A relay device that is mounted on the vehicle side and amplifies and retransmits radio waves received from a wireless communication device mounted on a helmet worn by a passenger of the vehicle;
The relay device relays communication between wireless communication devices mounted on helmets worn by occupants of the same vehicle,
Communication between the wireless communication device mounted on the helmet worn by the vehicle occupant and the wireless communication device mounted on the helmet worn by a passenger on a vehicle different from the vehicle can be relayed. A configured radio communication system for a vehicle.  The vehicle radio communication system according to claim 1, wherein the radio wave transmitter / receiver is detachably attached to a rear center of the helmet via a detachable fixing member.  The relay device includes a mixing device to which at least one audio signal generating device that generates an audio signal is connected, and the audio signal output from each audio signal generating device is mixed with the received audio signal and transmitted. The vehicular wireless communication system according to claim 1 or 2.  The vehicular radio according to claim 3, wherein the relay device has a mute function for selectively muting (attenuating or blocking) at least one of audio signals output from each audio signal generating device. Communications system.  5. The vehicle radio communication system according to claim 4, wherein the audio signal generation device is at least one of a navigation system, a mobile phone, a music playback device, another radio device, and an audio board.  The vehicle radio communication system according to claim 1, wherein the radio wave transceiver includes a radio communication antenna.  The radio wave transmitter / receiver includes at least a circuit board and a battery, and the circuit board and the battery housing portion are distributed to the left and right when the radio wave transmitter / receiver is attached to the rear center of the helmet in a predetermined posture. The vehicular wireless communication system according to claim 1, wherein the vehicular radio communication system is arranged in a vehicle.  8. The vehicular wireless communication system according to claim 7, wherein the size of the battery accommodating portion is equivalent to an AA battery and equivalent to the circuit board.  The vehicle radio communication system according to claim 1, wherein the radio wave transmitter / receiver has an operation button disposed on a back surface when the radio transmitter / receiver is mounted in a predetermined posture at a rear center of the helmet.  6. The vehicular wireless communication system according to claim 5, wherein the display device of the navigation system is supported movably between a use position and a storage position. 1st node provided in the helmet which the driver | operator of a vehicle wears, and the radio | wireless communication system for vehicles which performs radio | wireless communication between the 2nd node mounted in the vehicle in which the driver | operator who wore the said helmet is riding In
The first node and the second node comprise Bluetooth standard wireless communication means, and perform multiple wireless communication using the first node as a master and the second node as a slave. Wireless communication system. As an external communication means for enabling communication to the outside of the vehicle, further comprising a mobile phone incorporating a Bluetooth standard module accessible from the first node and the second node,
The vehicle wireless communication system according to claim 11, wherein communication between the driver and the outside and between the vehicle and the outside is enabled via the mobile phone.  The vehicle wireless communication system according to claim 12, wherein wireless communication is performed between the driver, the vehicle, and external communication means. n nodes corresponding to each of n helmets (n is an integer of 2 or more),
While wirelessly communicating between the n nodes,
12. The vehicular wireless communication system according to claim 11, wherein each of the plurality of nodes is divided into full-duplex communication and other than that.  The vehicle wireless communication system according to claim 14, wherein transmission of vehicle travel information performed between the first node and the second node is performed by full-duplex communication. A wireless communication device attached to each helmet worn by a vehicle occupant;
A relay device mounted on the vehicle side and communicating with the wireless communication device;
Each of the wireless communication devices communicates directly with each other without using the relay device in near field communication in which the received radio wave intensity is equal to or greater than a predetermined threshold, and A wireless communication system for vehicles, wherein communication is performed via a relay device.

Images