JP7055683B2 - In-vehicle communication device and wireless communication method - Google Patents

Description

Embodiments of the present invention relate to in-vehicle communication devices and wireless communication methods.

In recent years, many vehicles are equipped with an in-vehicle communication device, and the in-vehicle communication device communicates with an entrance / exit of a parking lot or a toll road, and a roadside communication device installed on the roadside, etc., and information for collecting tolls or road conditions. Etc. can be sent and received. The ETC (Electronic Toll Collection System) is well known as a system for collecting charges by communication between an in-vehicle communication device and a roadside communication device.

The government is aiming to realize advanced frequency use in order to realize the world's most advanced safe, secure and comfortable connected car society by 2020. Specifically, it is as follows.
・ Sophistication of ITS Connect in the 700MHz band (ITS: Intelligent Transport Systems)
・ Sophistication of DSRC system (DSRC: Dedicated Short Range Communications)
・ Realization of intelligent ITS communication (V2X) system (V2X: Vehicle-to-everything)
Among them, for advanced ITS communication, a system using IEEE 802 base or mobile 5th generation (5G) is being studied. However, the 700MHz band is an effective frequency band for ITS because it enables non-line-of-sight vehicle-to-vehicle communication and road-to-vehicle communication, but the band is only 10MHz, and the band is too narrow for V2X. On the other hand, in the 5GHz band, the frequency band is tight as in recent trends such as wireless LAN. Therefore, 5,770-5,850 MHz, which is currently assigned to DSRC, is promising as a frequency for realizing intelligent ITS communication.

However, this frequency band is currently used for private applications such as ETC, ITS spots, and parking lots. Therefore, it is expected that after 2020, existing systems such as ETC and advanced ITS communication systems will be shared. Therefore, it is important to avoid interference so as not to affect the operation of the existing system.

Japanese Unexamined Patent Publication No. 2011-191946 Japanese Unexamined Patent Publication No. 2017-41749 Japanese Unexamined Patent Publication No. 2010-23307

For example, in ETC, when an advanced ITS communication system communicates on the same channel or a adjacent channel near a tollhouse, interference from the advanced ITS communication system may affect the opening and closing of gates and proper billing. There is sex. There is a demand for a technique for avoiding such communication interference and realizing gate opening / closing and proper billing.

In Europe, there are standards for sharing DSRC systems with intelligent ITS communication systems. This standard avoids interference by reducing the output power of advanced ITS communication and lengthening the communication interval when interference with DSRC is expected when performing advanced ITS communication. This is established as an interference avoidance technique because the frequency band used in advanced ITS communication and the frequency band used in ETC are different.

However, in the same frequency band (5,770-5,850 MHz), it is difficult to avoid interference with DSRC by reducing the output power of the advanced ITS communication and increasing the communication interval.

An object of the present invention is to provide an in-vehicle communication device and a wireless communication method excellent in avoiding interference when communicating with different parties such as a mobile station and a base station.

The vehicle-mounted communication device according to the embodiment includes an information acquisition unit, a wireless communication unit, and a control unit. The information acquisition unit acquires position information indicating the current position. The wireless communication unit communicates with another in-vehicle communication device in a frequency band selected from one of the first and second frequency bands, and also communicates with a base station to receive a dynamic map, and the second frequency band. Communicates with the ETC communication device. The control unit detects the position of the ETC communication device on the road map from the dynamic map, estimates the communication area of the ETC communication device from the position of the ETC communication device on the road map, and the second frequency band. While communicating with the other in-vehicle communication device on the communication channel, it is determined to switch the communication channel based on the current position and the communication area, and the communication channel is selected from the empty channels in the first frequency band. Switch to the selected channel and continue communication with the other in-vehicle communication device.

It is a schematic diagram which shows an example of the wireless communication system which concerns on embodiment. It is a block diagram which shows an example of the in-vehicle communication apparatus applied to the wireless communication system which concerns on embodiment. It is a block diagram which shows an example of the base station applied to the wireless communication system which concerns on embodiment. It is a block diagram which shows an example of the ETC communication apparatus applied to the wireless communication system which concerns on embodiment. It is a figure which shows the use example of a channel of 5.8GHz band. It is a flowchart which shows an example of the wireless communication processing by the wireless communication system which concerns on embodiment.

Hereinafter, embodiments will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of a wireless communication system according to an embodiment.
As shown in FIG. 1, the wireless communication system includes an in-vehicle communication device (mobile station) 1, a DSRC base station 2, and an ETC communication device 4 mounted on each vehicle. The in-vehicle communication device 1 includes an in-vehicle antenna AT1, the DSRC base station 2 includes an antenna AT2, and the ETC communication device 4 includes an ETC antenna AT4. The area surrounded by the broken line in FIG. 1 indicates the ETC communication area E of the ETC antenna AT4.

The ETC antenna AT4 is an antenna for DSRC provided in front of the entrance and exit of the toll road, and the communication area of the antenna AT2 of the DSRC base station 2 is wide, whereas the communication area of the ETC antenna AT4 is ETC communication area E. Is a narrow area.

As shown in FIG. 1, outside the ETC communication area E, the in-vehicle communication device 1 communicates with the antenna AT2 of the DSRC base station 2 using radio waves in a frequency band selected from the 5.8 GHz band and the 700 MHz band, and provides information. To send and receive. The vehicle-mounted communication device 1 periodically receives the dynamic map transmitted from the antenna AT2. Such communication between the vehicle-mounted communication device 1 and the antenna AT2 of the DSRC base station 2 is called road-to-vehicle communication. The 700 MHz band is referred to as a first frequency band, and the 5.8 GHz band is referred to as a second frequency band.

Further, outside the ETC communication area E, the in-vehicle communication device 1 of a certain vehicle (hereinafter referred to as the first vehicle) uses radio waves in a frequency band selected from one of the 5.8 GHz band and the 700 MHz band to another vehicle. Communicates with the vehicle-mounted communication device 1 (hereinafter referred to as the second vehicle) to transmit and receive information. Such communication between different vehicles (communication between a plurality of in-vehicle communication devices 1) is referred to as vehicle-to-vehicle communication. By vehicle-to-vehicle communication, information on the behavior of the vehicle is exchanged between the first vehicle and the second vehicle, and automatic driving control including collision avoidance is realized.

Further, inside the ETC communication area E, the vehicle-mounted communication device 1 communicates with the ETC antenna AT4 of the ETC communication device 4 using radio waves in the 5.8 GHz band, and transmits / receives information. Similar to the above, such communication between the vehicle-mounted communication device 1 and the ETC antenna AT4 of the ETC communication device 4 is also referred to as road-to-vehicle communication. The inter-vehicle communication (communication switching process, etc.) inside the ETC communication area E will be described in detail later.

FIG. 2 is a block diagram showing an example of an in-vehicle communication device applied to the wireless communication system according to the embodiment.
As shown in FIG. 2, the vehicle-mounted communication device 1 includes an vehicle-mounted antenna AT1, a control unit 11, a storage unit 12, a wireless communication unit 14, an information input unit 15, an information output unit 16, a reader / writer 17, and an information acquisition unit 18. Be prepared.

The in-vehicle antenna AT1 communicates with the antenna AT2 of the DSRC base station 2 and transmits / receives information by radio waves in a frequency band selected from the 5.8 GHz band and the 700 MHz band. The vehicle-mounted antenna AT1 receives the dynamic map transmitted from the antenna AT2. Further, the vehicle-mounted antenna AT1 of the vehicle-mounted communication device 1 of the first vehicle communicates with the vehicle-mounted antenna AT1 of the vehicle-mounted communication device 1 of the second vehicle by radio waves in a frequency band selected from the 5.8 GHz band and the 700 MHz band for information. To send and receive. Further, the vehicle-mounted antenna AT1 communicates with the ETC antenna AT4 of the ETC communication device 4 by radio waves in the 5.8 GHz band to transmit and receive information.

The control unit 11 includes one or more processors and a memory, for example, the processor is a CPU (Central Processing Unit). The processor is connected to each part of the vehicle-mounted communication device 1 via a bus. The processor controls the operation of each unit by executing a program stored in at least one of the memory and the storage unit 12.

The storage unit 12 includes a read-only memory and a rewritable non-volatile memory. The storage unit 12 stores programs, control data, transmission / reception data, identification information unique to the vehicle-mounted communication device 1, and the like.

The wireless communication unit 14 extracts a modulated signal from the received RF (Radio Frequency) signal received by the vehicle-mounted antenna AT1 and demodulates it, and outputs the received data generated to the control unit 11. Further, the wireless communication unit 14 generates a transmission RF signal from the modulated signal generated by modulating the transmission data from the control unit 11 and outputs the transmission RF signal to the in-vehicle antenna AT1.

The information input unit 15 is provided with an input key or the like, receives an input from a user, and outputs the input information to the control unit 11. For example, the information input unit 15 receives inputs related to various settings of the in-vehicle communication device 1.

The information output unit 16 includes a display, a speaker, and the like, and displays information such as an operating state, a processing result, and a determination result. For example, the information output unit 16 displays entrance information, exit information, toll charges (billing information), etc. transmitted from the ETC antenna AT4. The entrance information includes information such as identification information of an entrance such as a toll road, an entrance name, and an entrance date and time. The exit information includes information such as identification information of an exit such as a toll road, an exit name, and an exit date and time.

The reader / writer 17 communicates with the ETC card 1a loaded in the vehicle-mounted communication device 1, writes information (entrance information or exit information) in the ETC card 1a, and reads the information (identification information) written in the ETC card 1a. Or something.

The information acquisition unit 18 periodically acquires the current position information. For example, the information acquisition unit 18 periodically receives radio waves from a plurality of GPS (Global Positioning System) satellites, transmits the received data to the GPS server, and receives the position information required by the GPS server. The information acquisition unit 18 includes an interface for connecting to an external device (for example, a navigation system and a vehicle travel control system) mounted on the vehicle of the vehicle-mounted communication device 1, and the current position of the vehicle and the vehicle provided by the navigation system. A high-precision three-dimensional road map including the traveling direction of the vehicle, and vehicle speed information provided by the travel control system may be acquired. The three-dimensional road map contains information such as flat roads, underpasses, and viaduct roads. In addition, the road map also includes information such as general roads, toll roads, and three-dimensional intersections located on the upper and lower floors.

FIG. 3 is a block diagram showing an example of a base station applied to the wireless communication system according to the embodiment.
The DSRC base station 2 includes an edge computer 21, a signal processing unit 22, a wireless communication unit 23, and an antenna AT2.

The edge computer 21 is a control unit composed of one or more processors and a memory, communicates with the upper server S2, and receives a dynamic map. Further, the edge computer 21 communicates with the upper server S2 and executes the application. In intelligent ITS communication, there are some applications such as applications related to safety and security that require communication with low delay. In this case, since it may not be in time for data communication with the host server S2, the edge computer 21 is provided in the DSRC base station 2, and the edge computer 21 realizes a low-delay application. In particular, the edge computer 21 processes information that changes from moment to moment, such as traffic congestion and the progress of surrounding vehicles, in the dynamic map.

The dynamic map is information that combines a static and highly accurate three-dimensional road map with dynamic location information such as traffic congestion information and traffic regulation. This dynamic map is used for autonomous driving. The three-dimensional road map includes building information such as buildings, information on free space roads such as flat roads and viaduct roads, and information on closed space roads such as tunnels and underpasses. Furthermore, the three-dimensional road map also includes information such as general roads, toll roads, and three-dimensional intersections located on the upper and lower floors. Further, the dynamic map includes ETC-related information regarding each ETC communication device 4. The ETC-related information includes the position information of each ETC communication device 4 associated with the three-dimensional road map. That is, the ETC information includes information indicating whether the ETC communication device 4 is provided on the road in free space or the ETC communication device 4 is provided on the road in closed space. Further, the ETC-related information includes information indicating the ETC communication area E of each ETC communication device 4. Further, the ETC-related information includes the attribute information of the ETC communication area E. The attribute information indicates the road information to which the ETC communication area E belongs, the information on the frequency channel used in the ETC communication area E, the information on the direction of the ETC antenna AT4, the radio wave strength information indicating the radio wave strength level, and the radio wave shielding level. Includes radio wave shielding information.

For example, the road information included in the attribute information is information indicating on which road the ETC communication area E exists. By referring to this information, which road of the multiple roads installed in the horizontal direction (horizontal direction) is the communication area, and which road of the multiple roads installed in the vertical direction (vertical direction). You can know if it is a communication area that exists in. For example, the influence of radio waves radiated in the ETC communication area E provided on a certain road is relatively higher on the roads located in the vertical direction of the certain road than on the roads located in the left-right direction of the certain road. And. The ETC tollhouse may be provided with a shielding wall as a soundproofing and magnetic shielding measure, and the influence of the shielding reduces the influence of radio waves in the left-right direction. Also, when viewed only in the vertical direction, it is assumed that the height is relatively higher for a road located below a certain road than for a road located above a certain road. In addition, various shielding walls are provided at the ETC tollhouse according to the surrounding environment of the tollhouse. For example, if the surrounding environment of the tollhouse is a residential area, a high and long shield wall may be installed, and if it is a suburb, a simple shield wall may be installed. As described above, the ETC tollhouse is provided with a shielding wall having a different shielding level depending on the surrounding environment of the tollhouse, and the shielding level of the shielding wall can be known from the radio wave shielding information.

At the time of signal transmission, the signal processing unit 22 modulates the transmission data from the edge computer 21 and outputs the modulated signal to the wireless communication unit 23. Further, when the signal is received, the signal processing unit 22 demodulates the modulated signal from the wireless communication unit 23 and outputs the received data to the edge computer 21.

At the time of signal transmission, the wireless communication unit 23 generates a transmission RF signal from the modulated signal from the signal processing unit 22 and outputs the transmission RF signal to the antenna AT2. Further, when the signal is received, the wireless communication unit 23 extracts and outputs a modulated signal from the received RF signal received by the antenna AT2.

At the time of signal transmission, the antenna AT2 inputs a transmission RF signal from the wireless communication unit 23 and radiates the transmission RF signal into space. Further, when the antenna AT2 receives the signal, the antenna AT2 receives the RF signal from the space and outputs the received RF signal to the wireless communication unit 23. For example, the antenna AT2 transmits / receives information using a frequency band selected from one of the 5.8 GHz band and the 700 MHz band. The antenna AT2 transmits the above-mentioned dynamic map.

FIG. 4 is a block diagram showing an example of an ETC communication device applied to the wireless communication system according to the embodiment.
As shown in FIG. 4, the ETC communication device 4 includes an ETC antenna AT4, a control unit 41, a signal processing unit 42, and a DSRC communication unit 44.

The control unit 41 includes one or more processors and a memory, for example, the processor is a CPU. The processor is connected to each part of the ETC communication device 4 via a bus. The processor controls the operation of each part by executing a program stored in the memory. Further, the control unit 41 communicates with the lane server S4 and passes the information from the lane server S4 to the signal processing unit 42.

The signal processing unit 42 generates a modulated signal reflecting transmission data such as entrance information, exit information, and tolls from the lane server S4, outputs it to the DSRC communication unit 44, and also outputs the modulated signal to the DSRC communication unit 44. Modulates the modulated signal of the above and outputs it to the control unit 41 as received data.

The DSRC communication unit 44 generates a transmission RF signal from the modulation signal and outputs it to the ETC antenna AT4, extracts a modulation signal from the reception RF signal received by the ETC antenna AT4, and outputs the modulation signal to the signal processing unit 42.

The ETC antenna AT4 inputs a transmission RF signal from the DSRC communication unit 44 and radiates the transmission RF signal into space. Further, the ETC antenna AT4 receives an RF signal from space and outputs the received RF signal to the DSRC communication unit 44. For example, the ETC antenna AT4 transmits / receives information using some ETC channels in the 5.8 GHz band.

The ETC antenna AT4 communicates with the vehicle-mounted communication device 1 and receives the identification information of the vehicle-mounted communication device 1 and the identification information of the ETC card loaded in the vehicle-mounted communication device 1. Further, if the ETC antenna AT4 is provided at the entrance of the toll road, it communicates with the in-vehicle communication device 1 and transmits the entrance information. If the ETC antenna AT4 is provided at the exit of the toll road, it communicates with the in-vehicle communication device 1 and transmits exit information, tolls, and the like. Correctly transmitting and receiving information by the ETC antenna AT4 without being interfered with by other communications is important for executing correct billing processing.

FIG. 5 is a diagram showing an example of using a channel in the 5.8 GHz band.
As shown in FIG. 5, a plurality of channels included in 5,775 MHz to 5,805 MHz are assigned as downlinks, and a plurality of channels included in 5,815 to 5,845 MHz are assigned as uplinks. As the channel used in ETC, 5,795 MHz or 5,805 MHz is used for communication (downlink) from the ETC communication device 4 (ETC antenna AT4) to the vehicle-mounted communication device 1 (vehicle-mounted antenna AT1), and the vehicle-mounted communication device 1 In the communication (uplink) from the (vehicle-mounted antenna AT1) to the ETC communication device 4 (ETC antenna AT4), 5,835 MHz or 5,845 MHz is used.

Each channel included in 5,775-5,805MHz is called a downlink channel, and each channel included in 5,815-5,845MHz is called an uplink channel. The 5,795MHz, 5,805MHz, 5,835MHz, and 5,845MHz channels are called ETC channels, of which the 5,795MHz and 5,805MHz channels are called ETC downlink channels, and the 5,835MHz and 5,845MHz channels are called ETC uplink channels. Call. Further, in the channels shown in FIG. 5, channels other than the ETC channel will be referred to as ETC 2.0 channels for convenience. Furthermore, among the uplink channels, each channel of 5,815MHz, 5,820MHz, 5,825MHz, and 5,830MHz will be referred to as an advanced information channel. Alternatively, the 5,815MHz, 5,820MHz, and 5,825MHz channels that are separated from the frequencies of the ETC uplink channels (5,835HzMHz and 5,845HzMHz) may be referred to as advanced information channels.

For example, in a road environment where the distance between tollhouses is short and the distance between ETC communication area E and ETC2.0 (ITS communication area) is short, ETC channel and ETC2.0 channel are used properly in order to avoid communication interference between them. Operate. On the contrary, in a road environment where the distance between tollhouses is long and the distance between ETC communication area E and ETC 2.0 is long, communication interference between the two is unlikely to occur, so each channel included in 5,775 to 5,845 MHz is ETC 2.0 channel. It is also possible to use it as an operation.

FIG. 6 is a flowchart showing an example of wireless communication processing by the wireless communication system according to the embodiment. The wireless communication process according to the embodiment will be described with reference to FIGS. 1 and 6.

The information acquisition unit 18 of the vehicle-mounted communication device 1 periodically acquires a three-dimensional road map including the current position of the vehicle and the traveling direction of the vehicle from the navigation system or the like (step ST101). As shown in FIG. 1, outside the ETC communication area E, it is assumed that the vehicle-to-vehicle communication device 1 of the first vehicle and the vehicle-mounted communication device 1 of the second vehicle are in communication with each other. The control unit 11 and the wireless communication unit 14 of the vehicle-mounted communication device 1 of the first vehicle select one of a predetermined frequency band, for example, 700 MHz band or 5.8 GHz band, and search for an empty channel in the selected frequency band. , Communicates with the in-vehicle communication device 1 of the second vehicle on an empty channel. For example, if the 700MHz band is preferentially selected and there are no free channels in the 700MHz band, the 5.8GHz band is selected and the free channels in the 5.8GHz band are searched.

When the vehicle-mounted communication device 1 of the first vehicle enters the communication area of the antenna AT2 as the first vehicle travels, the vehicle-mounted antenna AT1 and the wireless communication unit 14 periodically transmit from the antenna AT2. The map is received (step ST102), and the storage unit 12 stores the dynamic map (step ST103). The control unit 11 updates the dynamic map stored in the storage unit 12 to the latest dynamic map in response to the reception of the dynamic map. As a result, even when traveling in an area where the dynamic map cannot be received (in a tunnel, etc.), the dynamic map received immediately before can be used.

The control unit 11 detects the position of the ETC communication device 4 on the road map from the dynamic map, and estimates the ETC communication area E'of the ETC communication device 4 from the position of the ETC communication device 4 on the road map. That is, the control unit 11 refers to the road map and estimates the ETC communication area E'based on the installation conditions of the ETC communication device 4. The ETC communication area E shown in FIG. 1 is a theoretical communication area, and the ETC communication area E'estimated by the control unit 11 becomes substantially the same as the ETC communication area E depending on the installation conditions of the ETC communication device 4. Sometimes.

For example, when the control unit 11 refers to the road map and determines that the ETC communication device 4 is installed on a flat ground or a viaduct road (free space) without a large building in the vicinity, the ETC communication device 4 is used. The first ETC communication area E'including the first communication distance is estimated from the position.

Further, when the control unit 11 refers to the road map and determines that the ETC communication device 4 is installed in a tunnel or an underpass (closed space), the control unit 11 includes a second communication distance from the position of the ETC communication device 4. The second ETC communication area E'is estimated. The second communication distance is longer than the first communication distance. That is, the communication distance of the ETC communication device 4 installed in the closed space is set longer than the communication distance of the ETC communication device 4 installed in the free space.

Further, the control unit 11 refers to the road map, and when a large building is installed around the ETC communication device 4, the ETC communication device 4 is installed on a flat ground or a high bridge road (free space). Also, it is determined that the ETC communication device 4 is installed in the semi-closed space, and the third ETC communication area E'including the third communication distance is estimated from the position of the ETC communication device 4. The third communication process is longer than the first communication distance and shorter than the second communication distance. That is, the communication distance of the ETC communication device 4 installed in the semi-closed space is made longer than the communication distance of the ETC communication device 4 installed in the free space, and the communication distance of the ETC communication device 4 installed in the closed space is semi-closed. The communication distance of the ETC communication device 4 installed in the space is set short.

The control unit 11 collates the road map from the navigation system or the like with the dynamic map from the base station 2, and the communication channel is based on the current position included in the road map from the navigation system or the like and the estimated ETC communication area E'. Judge the necessity of switching. The control unit 11 compares the distance from the current position included in the road map from the navigation system or the like to the ETC communication area E'(the outer edge of the ETC communication area E') and the proximity determination threshold value (for example, 100 m), and the distance thereof. When is equal to or less than the proximity determination threshold value, it is determined that the ETC communication area E'is in a proximity state (step ST104). Further, the control unit 11 compares the distance from the current position to the ETC communication area E'(the center of the ETC communication area E') with the approach determination threshold value, and when the distance becomes equal to or less than the approach determination threshold value, the ETC communication area E It may be determined that it is in the state of entry to'.

Further, as described below, the proximity determination threshold value or the approach determination threshold value may be changed to determine the proximity state or the approach state.

(1) Change of proximity determination threshold value or approach determination threshold value based on radio wave intensity information As described above, the dynamic map includes radio wave intensity information indicating the radio field intensity level of the ETC communication area E. The control unit 11 detects the radio wave intensity information indicating the radio wave intensity level of the ETC communication area E from the dynamic map, and changes the proximity determination threshold value or the approach determination threshold value according to the radio wave intensity information. When the radio wave intensity level is high, the control unit 11 changes the proximity determination threshold value or the approach determination threshold value to a value larger than the reference value (for example, 100 m), and the outer edge of the ETC communication area E'(ETC communication area E') from the current position or While the distance to the center) is long, the proximity state or the approach state is determined. On the contrary, when the radio wave intensity level is low, the control unit 11 changes the proximity determination threshold value or the approach determination threshold value to a value smaller than the reference value, and determines the proximity state or the approach state.

(2) Change of proximity determination threshold value or approach determination threshold value based on radio wave shielding information As described above, the dynamic map includes radio wave shielding information indicating the radio wave shielding level of the ETC communication area E. The control unit 11 detects radio wave shielding information indicating the radio wave shielding level of the ETC communication area E from the dynamic map, and changes the proximity determination threshold value or the approach determination threshold value according to the radio wave shielding information. When the radio wave shielding level is low, the control unit 11 changes the proximity determination threshold value or the approach determination threshold value to a value higher than the reference value, and extends from the current position to the ETC communication area E'(the outer edge or the center of the ETC communication area E'). While the distance is long, the proximity state or the approach state is determined. On the contrary, when the radio wave shielding level is high, the control unit 11 changes the proximity determination threshold value or the approach determination threshold value to a value smaller than the reference value, and determines the proximity state or the approach state. When the radio wave shielding level is high, in a case where the vehicle travels on a road different from the road in the ETC communication area E, the influence of radio wave interference is reduced due to the shielding.

(3) Change of proximity determination threshold value or approach determination threshold value due to difference in road As described above, the information acquisition unit 18 acquires a road map including the current position of the vehicle and the traveling direction of the vehicle. The control unit 11 collates the road map from the navigation system or the like with the dynamic map from the base station 2, determines whether the road on which the vehicle is traveling and the road on which the ETC communication area E'exists are the same, and the same. The proximity judgment threshold value or the approach judgment threshold value is changed depending on whether the case is different from the case. When the road on which the vehicle is traveling and the road on which the ETC communication area E'exists are the same, the control unit 11 changes the proximity determination threshold value or the approach determination threshold value to a value higher than the reference value, and the ETC communication area E from the current position. While the distance to'(the outer edge or the center of the ETC communication area E') is long, the proximity state or the approach state is determined in preparation for the ETC communication area E'which will be reached soon. Further, when the road on which the vehicle is traveling and the road on which the ETC communication area E'exists are different, the control unit 11 changes the proximity determination threshold value to a value smaller than the reference value, and determines the proximity state or the approach state.

(4) Change of proximity determination threshold value or approach determination threshold value due to difference in road (vertical direction or left-right direction) As described above, the information acquisition unit 18 acquires a road map including the current position of the vehicle and the traveling direction of the vehicle. .. The control unit 11 collates the road map from the navigation system or the like with the dynamic map from the base station 2, determines whether the road on which the vehicle is traveling and the road on which the ETC communication area E'exists are different in the vertical direction. Further, it is determined whether or not the difference is in the horizontal direction, and the proximity judgment threshold or the approach judgment threshold is changed depending on whether the difference is in the vertical direction or the horizontal direction. When the road on which the vehicle is traveling and the road on which the ETC communication area E'exists are different in the vertical direction, the control unit 11 changes the proximity determination threshold value or the approach determination threshold value to a value higher than the reference value, and ETC communication is performed from the current position. While the distance to the area E'(the outer edge or the center of the ETC communication area E') is long, the proximity state or the approach state is determined. Since the influence of radio waves due to the difference in the vertical position is relatively large, the proximity state or the approach state is determined early. Further, when the road on which the vehicle is traveling and the road on which the ETC communication area E'exists are different in the horizontal direction, the control unit 11 changes the proximity determination threshold value or the approach determination threshold value to a value smaller than the reference value, and the proximity state or Determine the approach state. Since the influence of radio waves due to the difference in horizontal position is relatively small (the influence is relatively small due to the effect of the shielding wall of the tollhouse), the proximity state or the approach state is judged later.

(5) Change of proximity determination threshold value or approach determination threshold value in a closed space or a semi-closed space As described above, the information acquisition unit 18 acquires a road map including the current position of the vehicle and the traveling direction of the vehicle. The control unit 11 collates the road map from the navigation system or the like with the dynamic map from the base station 2, determines whether or not the ETC communication area E'exists in a closed space such as a tunnel or an underpass, and exists in the closed space. If so, the proximity judgment threshold value or the approach judgment threshold value is changed. When the ETC communication area E'exists in a closed space such as a tunnel or an underpass, the control unit 11 changes the proximity determination threshold value or the approach determination threshold value to a value higher than the reference value, and the ETC communication area E'from the current position. While the distance to (the outer edge or the center of the ETC communication area E') is long, the proximity state or the approach state is determined. In a closed space, radio waves are easy to fly, and the influence of radio waves occurs in a wide range. Therefore, the proximity state or the approach state is determined early. Further, when the ETC communication area E'exists in the free space instead of the closed space, the control unit 11 determines the proximity state or the approach state without changing the proximity determination threshold value or the approach determination threshold value. Similarly, when the ETC communication area E'exists in the semi-closed space, the control unit 11 changes the proximity determination threshold value or the approach determination threshold value to a threshold value higher than the reference value and lower than the threshold value given in the closed space.

The control unit 11 may determine the proximity state based on the position information, the ETC communication area E', and the vehicle speed information. For example, when the control unit 11 detects the first speed from the vehicle speed information, the control unit 11 determines the proximity state by comparing with the first proximity determination threshold value, and from the vehicle speed information, the first speed is used. When detecting a fast second speed, the proximity state may be determined by comparing with the second proximity determination threshold value having a value larger than the first proximity determination threshold value. That is, the faster the vehicle speed is, the more the control unit 11 determines the proximity state before the ETC communication area E'.

The control unit 11 detects the status of vehicle-to-vehicle communication and controls the vehicle-to-vehicle communication according to the status of vehicle-to-vehicle communication. As described above, the ETC antenna AT4 transmits and receives information using some ETC channels in the 5.8 GHz band (see FIG. 5). Unless the control unit 11 determines the proximity state or the approach state to the ETC communication area E'during the inter-vehicle communication (step ST104, NO), the current state is maintained (step ST105). In this case, vehicle-to-vehicle communication continues.

The control unit 11 determines the proximity state or the approach state to the ETC communication area E'during the inter-vehicle communication (step ST104, YES), and determines that some ETC channels in the 5.8 GHz band are not used. Even so (step ST106, NO), the current status is maintained (step ST105).

When the control unit 11 determines that a part of the ETC channels in the 5.8 GHz band is used (step ST106, YES), the control unit 11 and the wireless communication unit 14 refer to the in-vehicle communication device of the second vehicle. , Declare the channel change (step ST107). The control unit 11 and the wireless communication unit 14 notify the vehicle-mounted communication device 1 of the second vehicle of the switching by the changed channel so that the vehicle-mounted communication device 1 of the second vehicle correctly reads the information after the channel change. Then communicate on the changed channel. If the control unit 11 and the wireless communication unit 14 do not receive the emergency information (step ST108, NO), the process proceeds to the communication switching process. When the control unit and the wireless communication unit 14 receive emergency information from the vehicle-mounted communication device of the second vehicle (step ST108, YES), the current vehicle-to-vehicle communication is continued (step ST109). The emergency information is warning information such as a collision, or a vehicle control signal for avoiding a collision or the like. After receiving the emergency information, the control unit 11 and the wireless communication unit 14 shift to the communication switching process.

In the communication switching process, the control unit 11 and the wireless communication unit 14 search for a free channel, and when a free channel is detected from the 700 MHz band (step ST110, YES), select a predetermined channel (changed channel) from the free channels. Then, the selected change channel is notified to the vehicle-mounted communication device 1 of the second vehicle, the approval response from the vehicle-mounted communication device 1 of the second vehicle is received, and the inter-vehicle communication is changed to the selected change channel (step ST113). ).

When the control unit 11 and the wireless communication unit 14 cannot detect a free channel from the 700 MHz band (step ST110, NO) and detect a free channel from some ETC 2.0 channels (other than the ETC channel) in the 5.8 GHz band. (Step ST111, YES) selects a predetermined channel (change channel) from the vacant channels, notifies the in-vehicle communication device 1 of the second vehicle of the selected change channel, and from the in-vehicle communication device 1 of the second vehicle. Upon receiving the approval response, the inter-vehicle communication is changed to the selected change channel (step ST113). In this way, by changing the inter-vehicle communication to the ETC 2.0 channel when the vehicle is close to the ETC communication area E', it is possible to avoid interference with the communication by the ETC channel in the ETC communication area E'.

Alternatively, when the control unit 11 and the wireless communication unit 14 cannot detect a free channel from the 700 MHz band, the free channel is detected by targeting the uplink channel among some ETC 2.0 channels in the 5.8 GHz band. You may do it. When the control unit 11 and the wireless communication unit 14 detect a vacant channel from the uplink channel, the control unit 11 selects a predetermined channel (change channel) from the vacant channel, and the selected change channel is used as the vehicle-mounted communication device 1 of the second vehicle. Is notified, the approval response from the in-vehicle communication device 1 of the second vehicle is received, and the inter-vehicle communication is changed to the selected change channel. As a result, the information after the channel change is correctly read by the vehicle-mounted communication device 1 of the second vehicle. In this way, by changing the inter-vehicle communication to the uplink channel when the ETC communication area E'is close to the ETC communication area E', it is possible to avoid interference with the communication by the ETC channel in the ETC communication area E'. In addition, by using the uplink channel, interference with the ETC downlink channel can be more reliably avoided.

Alternatively, when the control unit 11 and the wireless communication unit 14 cannot detect a free channel from the 700 MHz band, the free channel may be detected for a part of the advanced information channels in the 5.8 GHz band. When the control unit 11 and the wireless communication unit 14 detect a vacant channel from the advanced information channel, the control unit 11 selects a predetermined channel (change channel) from the vacant channel, and the selected change channel is used as the in-vehicle communication device of the second vehicle. 1 is notified, the approval response from the in-vehicle communication device 1 of the second vehicle is received, and the inter-vehicle communication is changed to the selected change channel. As a result, the information after the channel change is correctly read by the vehicle-mounted communication device 1 of the second vehicle. In this way, when the vehicle is close to the ETC communication area E', by changing the inter-vehicle communication to the advanced information channel, it is possible to avoid interference with the communication by the ETC channel in the ETC communication area E'. In addition, by using the advanced information channel, it is possible to more reliably avoid the interference with the ETC downlink channel, and it is possible to more reliably avoid the interference with the ETC uplink channel.

When the control unit 11 and the wireless communication unit 14 cannot detect an empty channel from either the 700 MHz band or the 5.8 GHz band (excluding the ETC channel) (step ST111, NO), the inter-vehicle communication is interrupted (step ST112). For example, with this interruption as a temporary interruption, the control unit 11 and the wireless communication unit 14 periodically search for free channels. When the control unit 11 and the wireless communication unit 14 detect a free channel from the 700 MHz band (step ST110, YES), a predetermined channel (changed channel) is selected from the free channel, and a channel for inter-vehicle communication to the selected changed channel. (Step ST113), if a free channel cannot be detected from the 700MHz band (step ST110, NO) and a free channel is detected from the 5.8GHz band (excluding ETC channels) (step ST111, YES), it is free. A predetermined channel (change channel) is selected from the channels, and the inter-vehicle communication channel is changed to the selected change channel (step ST113).

In the above explanation, when a part of the ETC channel of the 5.8GHz band is used, the case of shifting to the communication switching process has been described, but the 5.8GHz band is not limited to a part of the 5.8GHz band. If it is used, it may shift to the communication switching process. In this case, the inter-vehicle communication will be positively changed from the 5.8GHz band to the 700MHz band, and the frequency will be significantly different between the 700MHz band inter-vehicle communication and the 5.8GHz band ETC communication. It can be definitely avoided.

If the emergency information is not detected, the inter-vehicle communication may be interrupted and the communication in the ETC communication area E'of the ETC antenna AT4 of the advance notice communication device 3 may be prioritized. As a result, the in-vehicle communication device 1 and the ETC antenna AT4 can communicate with each other without interfering with the inter-vehicle communication, and the toll collection can be performed correctly.

When the approach state is determined, the inter-vehicle communication may be interrupted and the communication in the ETC communication area E'of the ETC antenna AT4 of the advance notice communication device 3 may be prioritized. As a result, the in-vehicle communication device 1 and the ETC antenna AT4 can communicate with each other without interfering with the inter-vehicle communication, and the toll collection can be performed correctly.

In the above description, here, as an example of the execution state of the advanced ITS communication, the execution state of the vehicle-to-vehicle communication is mentioned and the case of switching the vehicle-to-vehicle communication has been described. Can also be applied. Further, although the case of switching the communication targeting the ETC communication area E'has been described, it can be applied not only to the ETC communication area E'but also to the switching of the communication targeting the communication area of the DSRC system.

According to the embodiment described above, it is possible to provide an advanced ITS communication system that does not interfere with DSRC systems such as ETC and ITS spots.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

1 ... In-vehicle communication device 1a ... ETC card 2 ... DSRC base station 3 ... Notice communication device (base station)
4 ... ETC communication device 5 ... ETC and advance notice communication device (DSRC base station)
11 ... Control unit 12 ... Storage unit 14 ... Wireless communication unit 15 ... Information input unit 16 ... Information output unit 17 ... Reader / writer 18 ... Information acquisition unit 21 ... Edge computer 22 ... Signal processing unit 23 ... Wireless communication unit 41 ... Control unit 42 ... Signal processing unit 44 ... DSRC communication unit

Claims (12)

An information acquisition unit that acquires location information indicating the current position,
Communicates with another in-vehicle communication device in a frequency band selected from one of a first frequency band and a second frequency band different from the first frequency band, and selects from one of the first and second frequency bands. A wireless communication unit that communicates with the base station in the frequency band, receives the dynamic map, and communicates with the ETC communication device in the second frequency band.
The position of the ETC communication device on the road map is detected from the dynamic map, the communication area of the ETC communication device is estimated from the position of the ETC communication device on the road map, and the communication channel in the second frequency band is used. While communicating with another in-vehicle communication device, the switching of the communication channel is determined based on the current position and the communication area, and the communication channel in the second frequency band is selected from the empty channels in the first frequency band. A control unit that switches to the selected channel and continues communication with the other in-vehicle communication device.
In-vehicle communication device. The control unit estimates a first communication area including the first communication distance from the position of the ETC communication device for the ETC communication device in the free space, and the ETC communication device for the ETC communication device in the closed space. The vehicle-mounted communication device according to claim 1, wherein a second communication area including a second communication distance longer than the first communication distance is estimated from the position of. When the distance from the current position to the communication area is equal to or less than the proximity determination threshold value, the control unit selects the communication channel in the second frequency band from the empty channels in the first frequency band. The vehicle-mounted communication device according to claim 1 or 2, which switches to and continues communication with the other vehicle-mounted communication device. The vehicle-mounted communication device according to claim 3, wherein the control unit detects radio wave intensity information indicating a radio wave intensity level of the communication area from the dynamic map, and changes the proximity determination threshold according to the radio wave intensity information. The in-vehicle communication device according to claim 3, wherein the control unit detects radio wave shielding information indicating a radio wave shielding level in the communication area from the dynamic map, and changes the proximity determination threshold value according to the radio wave shielding information. The information acquisition unit acquires a road map including the current position of the vehicle and the traveling direction of the vehicle.
The vehicle-mounted communication device according to claim 3, wherein the control unit changes the proximity determination threshold value depending on whether the road on which the vehicle is traveling and the road on which the communication area exists are the same or different. The information acquisition unit acquires a road map including the current position of the vehicle and the traveling direction of the vehicle.
The vehicle-mounted communication device according to claim 3, wherein the control unit changes the proximity determination threshold value depending on whether the road on which the vehicle is traveling and the road on which the communication area exists are different in the vertical direction and in the horizontal direction. The wireless communication unit communicates with the ETC communication device on the ETC channel included in the second frequency band, and communicates with the ETC communication device.
When the control unit is communicating with the other vehicle-mounted communication device on the ETC channel and the distance is equal to or less than the proximity determination threshold value, the control unit switches the ETC channel to the selected channel and communicates with the other vehicle-mounted communication device. The vehicle-mounted communication device according to any one of claims 3 to 5. When there is no free channel in the first frequency band, the control unit switches the ETC channel to the selected channel selected from the free channels other than the ETC channel in the second frequency band, and the other The vehicle-mounted communication device according to claim 8, which continues communication with the vehicle-mounted communication device. The in-vehicle communication device of the mobile station and the ETC communication device of the base station communicate with each other by an uplink channel from the mobile station to the base station and a downlink channel from the base station to the mobile station.
The control unit selects the ETC channel from the free channels among the uplink channels other than the ETC channel in the second frequency band when there is no free channel in the first frequency band. The vehicle-mounted communication device according to claim 8, which switches to a channel and continues communication with the other vehicle-mounted communication device. The wireless communication unit notifies the other in-vehicle communication device of the switching by the selected channel so that the other in-vehicle communication device reads the information of the selected channel, and then requests to communicate in the selected channel. An in-vehicle communication device according to any one of Items 1 to 10. Get the location information that shows the current position,
It communicates with the base station in a frequency band selected from one of the first frequency band and the second frequency band different from the first frequency band, and receives the dynamic map.
The position of the ETC communication device on the road map is detected from the dynamic map, the communication area of the ETC communication device is estimated from the position of the ETC communication device on the road map, and the communication channel of the second frequency band is used. During communication with the in-vehicle communication device, the switching of the communication channel is determined based on the current position and the communication area, and the communication channel in the second frequency band is selected from the empty channels in the first frequency band. A wireless communication method for switching to a selected channel and continuing communication with the other in-vehicle communication device.

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