JP4479247B2 - Vehicle communication device - Google Patents

Description

  The present invention relates to a vehicle communication device.

2. Description of the Related Art Conventionally, there is known a vehicle communication device that transmits information by communicating between the own vehicle and another vehicle or between the own vehicle and a road machine in the same frequency band (see, for example, Patent Documents 1 and 2). ). There is also known a vehicle communication device that selects a communication carrier that can perform the cheapest communication from a plurality of communication carriers (see, for example, Patent Document 3).
Japanese Patent Application Laid-Open No. 9-102055 JP-A-10-148665 Japanese Patent Laid-Open No. 9-18963

  However, in the conventional apparatus, no consideration is given to communication quality, and there is still room for improvement. That is, in the conventional devices described in Patent Documents 1 and 2, since the communication frequency between the own vehicle and the other vehicle, or between the own vehicle and the road machine is predetermined, even if the communication frequency is not appropriate, The communication frequency cannot be changed, and the communication quality cannot be improved. Further, even in the conventional apparatus described in Patent Document 3, since the communication carrier that can perform the cheapest communication is selected, there is a possibility that the communication quality may deteriorate even if the inexpensive communication can be performed.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a vehicle communication device capable of improving communication quality.

  The vehicle communication device of the present invention is mounted on the host vehicle and communicates with a communication destination wirelessly, and includes a plurality of wireless communication means and frequency calculation means. The plurality of wireless communication means can wirelessly communicate with the communication destination in different frequency bands, and the frequency calculation means determines the communication frequency for wireless communication with the communication destination based on the correlation data between the frequency and the throughput. Is to be calculated.

  Furthermore, the vehicle communication device of the present invention includes a selection unit and a state change unit. The selecting means is for selecting a wireless communication means to be used for wireless communication from a plurality of wireless communication means based on the communication frequency calculated by the frequency calculating means. The state changing unit is configured to set the wireless communication unit selected by the selection unit to a wireless communication enabled state, and to set the wireless communication unit not selected to a wireless communication disabled state.

  According to the present invention, since the communication frequency for wireless communication with the communication destination is calculated based on the correlation data between the frequency and the throughput, the communication frequency considering the communication speed that is one of the communication qualities is calculated. Can do. Since the wireless communication means to be used for wireless communication is selected from the plurality of wireless communication means based on the calculated communication frequency, the wireless communication means suitable in terms of communication speed is selected from the plurality of wireless communication means. You can choose.

  In addition, the selected wireless communication means is set in a wireless communication enabled state, and the wireless communication means not selected is set in a wireless communication disabled state. For this reason, wireless communication is performed by a wireless communication unit suitable for communication speed among a plurality of wireless communication units. Accordingly, communication quality can be improved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. In the following embodiments, the same or similar elements are denoted by the same reference numerals and description thereof is omitted.

  FIG. 1 is a schematic configuration diagram of a vehicle communication device according to the first embodiment. First, as shown in FIG. 1, a vehicle communication device 1 according to this embodiment is mounted on a host vehicle and communicates with a communication destination wirelessly. As the communication destination, for example, other vehicles that run around the host vehicle and road machines installed on the road and the like are applicable.

  The vehicle communication device 1 includes a wireless communication terminal (wireless communication means) 10 and an in-vehicle information terminal 20. A plurality of wireless communication terminals 10 are provided, each of which can wirelessly communicate with a communication destination in different frequency bands. Specifically, n (n is an integer of 2 or more) wireless communication terminals 10 are provided, and each wireless communication terminal 10 is configured to communicate in different frequency bands such as 5.2 GHz band and 2.4 GHz band. .

The in-vehicle information terminal 20 selects the wireless communication terminal 10 to be used for communication from the n wireless communication terminals 10 and performs wireless communication with the selected wireless communication terminal. The in-vehicle information terminal 20 has a function of calculating a communication frequency suitable for wireless communication, and selects any one of _n wireless communication terminals 10 ₁ to 10 _n according to the calculated communication frequency. It has become.

Next, specific configurations of the _n radio communication terminals 10 ₁ to 10 _n and the in-vehicle information terminal 20 will be described. The n radio communication terminals 10 ₁ to 10 _n are configured except that the communication frequency bands are different. There are the same, and to illustrate the first wireless communication terminal 10 ₁ as an example.

The first wireless communication terminal 10 ₁ includes a first data communication device 11 ₁ and the first communication interface 12 _1. First data communication device 11 ₁ is functioning as a master for transmitting and receiving data, by the ignition switch of the vehicle is turned on, so that the power is turned. The first communication device 11 ₁ is always a built-in small-sized battery may be configured to keep the on-state. In this case, the first communication device 11 ₁ in order to prevent depletion of the small battery, it is preferable to adopt a configuration for charging a small battery while traveling.

The first communication interface 12 ₁ is intended for connecting the in-vehicle information terminal 20. Similarly, vehicle information terminal 20 has a communication interface 21, these both connection between the first communication device 11 ₁ and the vehicle information terminal 20 is adapted to be made.

  The connection here is performed by mobile phone communication, wireless LAN (802.11a, 802.11b, 802.11g, etc.), DSRC, or the like. Specifically, the connection is made by wireless such as Bluetooth or infrared (IrDA), or wired such as RS-232C (serial interface), USB (Universal Serial Bus), UART (Universal Asynchronous Receiver Transmitter). It has become.

The configuration of the other radio communication terminal ₁₀ 2 to 10 _n, as described above, the same as the first wireless communication terminal 10 _1, respectively a data communication device ₁₁ 2 to 11 _n and the communication interface ₁₂ 2 to 12 _n And is connected to the in-vehicle information terminal 20 through the communication interfaces 12 _{2 to} 12 _n .

The communication interface 21 of the in-vehicle information terminal 20 includes a communication method change ready unit 21a. The communication system change ready unit 21a is set so that n radio communication terminals 10 ₁ to 10 _n can receive electrical signals. That is, the communication system change ready unit 21a is in a state where any one of the _n wireless communication terminals 10 ₁ to 10 _n can be selected.

  In addition to the communication interface 21, the in-vehicle information terminal 20 includes a data storage memory 22, a frequency calculation unit (frequency calculation unit) 23, a communication method selection unit (selection unit) 24, and a communication method change unit (state). Change means) 25.

  The data storage memory 22 stores correlation data between frequency and throughput. Here, correlation data between frequency and throughput will be described. FIG. 2 is an explanatory diagram showing an example of correlation data between frequency and throughput.

  As shown in the figure, the throughput varies depending on the frequency. Specifically, the throughput is 11 Mbps in the 2.4 GHz band and 54 Mbps in the 5.2 GHz band. This correlation data is for the case where the relative distance between the host vehicle and the communication destination is 0 m and the relative speed between the host vehicle and the communication destination is 0 km.

  The configuration of the in-vehicle information terminal 20 will be described again with reference to FIG. The frequency calculation unit 23 calculates a communication frequency for wireless communication with a communication destination based on correlation data (hereinafter referred to as reference correlation data) between the frequency and the throughput stored in the data storage memory 22. Specifically, the frequency calculation unit 23 calculates the frequency with the highest throughput as the communication frequency. Therefore, when the relative distance between the host vehicle and the communication destination is 0 m and the relative speed between the host vehicle and the communication destination is 0 km, the frequency calculation unit 23 calculates 5.2 GHz or more based on the data shown in FIG. It is calculated as a communication frequency, and 2.4 GHz is not calculated as a communication frequency.

The communication method selection unit 24 selects one radio communication terminal 10 to be used for radio communication from the _n radio communication terminals 10 ₁ to 10 _n based on the communication frequency calculated by the frequency calculation unit 23. is there. For example, when the relative distance between the host vehicle and the communication destination is 0 m and the relative speed between the host vehicle and the communication destination is 0 km, the frequency calculation unit 23 calculates a frequency of 5.2 GHz or more as the communication frequency as described above. To do. For this reason, if the wireless communication terminal 10 ₁ to 10 _n having the highest frequency band for wireless communication communicates at 5.2 GHz, the communication method selection unit 24 is set to 5.2 GHz. The wireless communication terminal 10 that can perform wireless communication is selected.

  The communication method change unit 25 sets the wireless communication terminal 10 selected by the communication method selection unit 24 to a wireless communication enabled state, and sets the wireless communication terminal 10 not selected to a wireless communication disabled state. That is, when the wireless communication terminal 10 capable of wireless communication at 5.2 GHz is selected, the 5.2 GHz wireless communication terminal 10 is set in a wireless communication enabled state, and other wireless communication terminals 10 such as 2.4 GHz cannot be wirelessly communicated. It will be in a state. The communication method changing unit 25 is configured to change the communication enabled / disabled state of the wireless communication terminal 10 through the communication interface 21.

  Further, the in-vehicle information terminal 20 includes a position information acquisition unit (position information acquisition unit) 26, a distance calculation unit (distance calculation unit) 27, a speed information acquisition unit (speed information acquisition unit) 28, a relative speed calculation unit (relative speed calculation). Means) 29, a map database (map storage means) 30, a building detection unit 31, a radio wave arrival estimation unit (communication availability estimation unit) 32, and a calculation information acquisition unit 33.

  The position information acquisition unit 26 acquires the position information of the host vehicle and the position information of the communication destination. The distance calculation unit 27 acquires the position information of the host vehicle and the position of the communication destination acquired by the position information acquisition unit 26. Based on the information, the distance between the two is calculated.

  Specifically, the position information acquisition unit 26 is configured to acquire position information of the host vehicle using a GPS, a gyro sensor, or the like. The position information acquisition unit 26 is configured to request position information from the communication destination and acquire the position information of the communication destination.

  The speed information acquisition unit 28 acquires the speed information of the host vehicle and the speed information of the communication destination. The relative speed calculation unit 29 acquires the speed information of the host vehicle acquired by the speed information acquisition unit 28 and the communication destination. Based on the speed information, the relative speed of the host vehicle with respect to the communication destination is calculated.

  Specifically, the speed information acquisition unit 28 is configured to acquire the speed of the host vehicle based on a pulse signal or the like from a vehicle speed sensor. Similarly to the position information acquisition unit 26, the speed information acquisition unit 28 requests speed information from the communication destination and acquires the speed information of the communication destination.

  The map database 30 stores map information including at least building information. The building detection unit 31 detects the scale of the building stored in the map database 30. That is, the building detection unit 31 detects the height, width, depth, etc. of the building stored in the map database 30.

The radio wave arrival estimation unit 32 determines whether or not the own vehicle is a communication destination based on the position information of the own vehicle and the position information of the communication destination acquired by the position information acquisition unit 26 and the building information stored in the map database 30. It is estimated whether or not wireless communication is possible. Specifically, the radio wave arrival estimation unit 32 estimates whether or not wireless communication is possible for each communication frequency of the _n wireless communication terminals 10 ₁ to 10 _n . That is, the radio wave arrival estimation unit 32 is configured to estimate “cannot wirelessly communicate with 5.2 GHz band communication but can wirelessly communicate with 2.4 GHz band”.

  The calculation information acquisition unit 33 acquires distance information, relative speed information, and estimation result information from the distance calculation unit 27, the relative speed calculation unit 29, and the radio wave arrival estimation unit 32. The calculation information acquisition unit 33 transmits these pieces of information to the frequency calculation unit 23.

  Here, in addition to the reference correlation data, the data storage memory 22 includes correlation data between distance and throughput (hereinafter referred to as distance correlation data), and correlation data between speed and throughput (hereinafter referred to as speed correlation data). Is remembered.

  The frequency calculation unit 23 has a first function for obtaining new reference correlation data based on the distance correlation data stored in advance in the data storage memory 22 and the distance calculated by the distance calculation unit 27. . Further, the frequency calculation unit 23 obtains new reference correlation data based on not only the distance but also the speed correlation data stored in advance in the data storage memory 22 and the relative speed calculated by the relative speed calculation unit 29. Has two functions. Furthermore, the frequency calculation unit 23 has a third function for obtaining new reference correlation data by setting the throughput to 0 Mbps when wireless communication is impossible.

  Hereinafter, the above three functions will be described. First, the distance correlation data is as follows. FIG. 3 is an explanatory diagram showing an example of the distance correlation data. As shown in the figure, the throughput varies depending on the communication distance. Specifically, when compared with the 2.4 GHz band and the 5.2 GHz band, the throughput is higher when the distance is short (about 17 m or less) and when the distance is longer (more than about 17 m), The 2.4 GHz band is higher. This distance correlation data is for the case where the relative speed of the host vehicle with respect to the communication destination is 0 km.

  Thus, the throughput varies depending on the communication distance, and there is a possibility that the communication frequency with the highest throughput cannot be calculated only with the reference correlation data shown in FIG. For this reason, the frequency calculation unit 23 has a first function, and a new reference correlation adapted to the current distance between the host vehicle and the other vehicle from the distance correlation data and the current distance between the host vehicle and the communication destination. The data is requested.

  Although the speed correlation data is not shown, the throughput varies depending on the speed between the two communicating parties, and tends to decrease as the relative speed increases. For this reason, as with the first function, the frequency calculation unit 23 has a second function, and obtains new reference correlation data adapted to the current relative speed of the host vehicle.

  Further, the third function is as follows. As described above, the radio wave arrival estimation unit 32 estimates that “wireless communication is not possible with 5.2 GHz band communication but wireless communication is possible with 2.4 GHz band communication”. In such a case, the frequency calculation unit 23 should not calculate the communication frequency as 5.2 GHz or more. For this reason, the frequency calculation unit 23 has a third function and obtains new reference correlation data in which the throughput of 5.2 GHz or more is 0 Mbps.

  Next, an outline of the operation of the vehicle communication device 1 according to the present embodiment will be described. First, the frequency calculation unit 23 loads reference correlation data as shown in FIG. And it will be in the standby state waiting for transmission of the distance information etc. from the calculation information acquisition part 33. FIG.

  During this standby state, first, the position information acquisition unit 26 acquires the position information of the host vehicle and the communication destination. Then, the position information acquisition unit 26 transmits the acquired position information to the distance calculation unit 27. Thereafter, the distance calculation unit 27 calculates the distance between the host vehicle and the communication destination, and transmits the distance information to the calculation information acquisition unit 33.

  Further, the speed information acquisition unit 28 acquires speed information of the host vehicle and the communication destination, and transmits the acquired speed information to the relative speed calculation unit 29. Then, the relative speed calculation unit 29 calculates the relative speed of the host vehicle with respect to the communication destination, and transmits the relative speed information to the calculation information acquisition unit 33.

  Further, the building detection unit 31 detects the scale of the building stored in the map database 30, and transmits information on the position and scale of the building to the radio wave arrival estimation unit 32. Further, the position information acquisition unit 26 transmits the position information of the host vehicle and the communication destination not only to the distance calculation unit 27 but also to the radio wave arrival estimation unit.

  Then, the radio wave arrival estimation unit 32 determines whether the host vehicle can wirelessly communicate with the communication destination based on the position information of the host vehicle and the communication destination, and the position and scale of the building stored in the map database 30. presume.

  Specifically, the radio wave arrival estimation unit 32 estimates whether or not wireless communication between the host vehicle and the communication destination is possible as shown in FIG. FIG. 4 is an explanatory diagram illustrating an example of an estimation method performed by the radio wave arrival estimation unit 32. In addition, although another vehicle is demonstrated to an example in FIG. 4 as a communication destination, the same process is performed even if a communication destination is a roadside machine.

  First, as shown in the figure, the radio wave arrival estimation unit 32 specifies both the positions O and P1 to P3 based on the position information of the host vehicle acquired by the position information acquisition unit 26 and the position information of the communication destination. Thereafter, the radio wave arrival estimation unit 32 identifies the positions P4 and P5 of the building and the scales S1 to S6 based on the information from the building detection unit 31.

  Thereafter, the radio wave arrival estimation unit 32 performs simulation. In the simulation, the radio wave arrival estimation unit 32 first specifies a communication frequency. After the identification, the radio wave arrival estimation unit 32 estimates the reflectance and transmittance from the type of building. Thereafter, the radio wave arrival estimation unit 32 calculates the incident angle and reflection angle of the radio wave on the building.

  Next, the radio wave arrival estimation unit 32 obtains the radio wave intensity after reflection of the building. Then, the above process is repeated until the radio wave intensity becomes “0”, and it is estimated whether or not the radio wave reaches another vehicle. After the estimation, the radio wave arrival estimation unit 32 repeatedly performs the above simulation at a frequency different from the specified frequency, and estimates whether the radio wave reaches other vehicles for each frequency.

  After the estimation, the radio wave arrival estimation unit 32 transmits the estimation result information to the calculation information acquisition unit 33. Then, the calculation information acquisition unit 33 transmits distance information, relative speed information, and estimation result information to the frequency calculation unit 23.

  Thereafter, the frequency calculation unit 23 obtains new reference correlation data using the first to third functions. FIG. 5 is an explanatory diagram illustrating an example of new reference correlation data obtained using the distance correlation data.

  First, in the first function, the frequency calculation unit 23 reads the distance correlation data stored in advance in the data storage memory 22 and inputs the distance information from the calculation information acquisition unit 33. And the frequency calculation part 23 calculates | requires new reference | standard correlation data based on distance information and distance correlation data.

  Specifically, when the distance is 0 m, the frequency calculation unit 23 obtains new reference correlation data that is about 11 Mbps in the 2.4 GHz band and about 54 Mbps in the 5.2 GHz band, as shown in FIG. When the distance is 10 m, new reference correlation data that is about 9 Mbps in the 2.4 GHz band and about 10.5 Mbps in the 5.2 GHz band is obtained. Further, when the distance is 20 m, new reference correlation data that is about 6 Mbps in the 2.4 GHz band and about 2 Mbps in the 5.2 GHz band is obtained.

  As described above, the frequency calculation unit 23 obtains new reference correlation data suitable for the distance from the host vehicle to the communication destination in the first function.

  Further, the frequency calculation unit 23 obtains new reference correlation data by the second function. FIG. 6 is an explanatory diagram showing an example of new reference correlation data obtained using the velocity correlation data.

  First, in the second function, the frequency calculation unit 23 reads the velocity correlation data stored in advance in the data storage memory 22 and inputs the relative velocity information from the calculation information acquisition unit 33. And the frequency calculation part 23 calculates | requires new reference | standard correlation data based on relative speed information and speed correlation data.

  Specifically, when the speed is 0 km / h, the frequency calculation unit 23 obtains new reference correlation data that is about 11 Mbps in the 2.4 GHz band and about 54 Mbps in the 5.2 GHz band, as shown in FIG. In addition, when the speed is 100 km / h, new reference correlation data that is about 2 Mbps in the 2.4 GHz band and about 12 Mbps in the 5.2 GHz band is obtained. Further, when the speed is 200 km / h, new reference correlation data that is about 0 Mbps in the 2.4 GHz band and about 2 Mbps in the 5.2 GHz band is obtained.

  Thus, the frequency calculation unit 23 obtains new reference correlation data that matches the speed of the host vehicle with respect to the communication destination in the second function.

  Moreover, the frequency calculation unit 23 obtains new reference correlation data also by the third function. In the third function, the frequency calculation unit 23 inputs information on the estimation result from the calculation information acquisition unit 33. And the frequency calculation part 23 calculates | requires new reference | standard correlation data based on the information data of an estimation result. For example, if a result indicating that communication is not possible at 5.2 GHz is obtained, the frequency calculation unit 23 obtains new reference correlation data with a 5.2 GHz throughput of 0 Mbps.

  In addition, in the above, in order to make an understanding easy, the 1st-3rd function was demonstrated separately and each calculated | required the process which calculates | requires new reference | standard correlation data. However, the frequency calculation unit 23 actually performs these three functions comprehensively, and new reference correlation data adapted to the distance from the own vehicle to the communication destination, the speed of the own vehicle with respect to the communication destination, and the arrival state of the radio wave. Will be asked.

  And after calculating | requiring new reference | standard correlation data by the 1st-3rd function, the frequency calculation part 23 calculates a communication frequency based on new reference | standard correlation data. At this time, the frequency calculation unit 23 calculates the frequency with the highest throughput as the communication frequency.

  For example, it is assumed that new reference correlation data obtained by comprehensively performing the first to third functions is as shown in FIG. Then, assuming that the distance between the host vehicle and the communication destination is 20 m, the frequency calculation unit 23 calculates 2.4 GHz as the communication frequency because the throughput is the highest at 2.4 GHz. On the other hand, when the distance between the host vehicle and the communication destination is 10 m, the throughput is highest at 5.2 GHz. For this reason, the frequency calculation unit 23 calculates 5.2 GHz as the communication frequency.

Then, the frequency calculation unit 23 transmits information on the calculated frequency to the communication method selection unit 24. The communication method selection unit 24 selects any one of the _n radio communication terminals 10 ₁ to 10 _n based on the communication frequency calculated by the frequency calculation unit 23. At this time, the communication method selection unit 24 selects the wireless communication terminal 10 that can communicate at a frequency closest to the calculated communication frequency. Then, the communication method selection unit 24 transmits information on the selected wireless communication terminal 10 to the communication method change unit 25.

  Thereafter, the communication method change unit 25 sets the wireless communication terminal 10 selected by the communication method selection unit 24 to a wireless communication enabled state, and sets the wireless communication terminal 10 not selected to a wireless communication disabled state. Thereby, this apparatus 1 can communicate by the radio | wireless communication terminal 10 by which the communication speed which is one of communication quality was made suitable.

Next, an example of detailed operation of the vehicle communication device 1 according to the present embodiment will be described. FIG. 7 is a flowchart showing an example of the operation of the vehicle communication device 1 according to the first embodiment. As shown in the figure, the apparatus 1 first performs initialization (ST10). FIG. 8 is a flowchart showing detailed processing of step ST10 shown in FIG. As shown in the figure, in the initialization, first, the in-vehicle information terminal 20 and the n wireless communication terminals 10 ₁ to 10 _n are physically connected (ST20). This connection process may be performed automatically when the ignition is turned on, or may be performed manually.

As an example performed manually, for example, a switch is connected to each other, and switches are provided in both the _n radio communication terminals 10 ₁ to 10 _n and the in-vehicle information terminal 20, and these switches are operated. There is a method of connecting by performing a specific operation. The physical connection here may be wired or wireless.

After the connection process, the in-vehicle information terminal 20 determines whether or not it is physically connected to the wireless communication terminals 10 ₁ to 10 _n (ST21). At this time, the in-vehicle information terminal 20 transmits, for example, an electrical signal (AT command or the like) to the n radio communication terminals 10 ₁ to 10 _n and determines whether there is a response.

  Here, if it is determined that the connection is not physically made (ST21: NO), the in-vehicle information terminal 20 determines whether or not the time during which the connection cannot be detected exceeds the specified time (ST22). When it is determined that the specified time is exceeded (ST22: YES), the process returns to step ST20, and the physical connection process is performed again.

On the other hand, when it is determined that the specified time is not exceeded (ST22: NO), the process returns to step ST21 and it is determined whether or not the connection is made again. On the other hand, when it is determined that they are connected (ST21: YES), the communication method change ready unit 21a sets the n radio communication terminals 10 ₁ to 10 _n in a selectable state (ST23). That is, the communication system change ready unit 21a is in a state in which an electrical signal can be received with respect to all the connected wireless communication terminals 10 ₁ to 10 _n .

  Thereafter, the communication method changing unit 25 electrically connects the wireless communication terminal 10 registered as the initial value (ST24). Then, after the electrical connection, the process returns to step ST11 in FIG.

Here, for example, when any one of the _n wireless communication terminals 10 ₁ to 10 _n is built in the in-vehicle information terminal 20, it is assumed that the built-in one is registered as an initial value. When there is no built-in wireless communication terminal 10, it is assumed that the first wireless communication terminal 10 physically connected is registered as an initial value. Furthermore, the wireless communication terminal 10 connected to the specific port may be registered as an initial value.

  Reference is again made to FIG. After initialization, the frequency calculation unit 23 loads the reference correlation data from the data storage memory 22 (ST11). Thereafter, the in-vehicle information terminal 20 calculates new reference correlation data (ST12).

  FIG. 9 is a flowchart showing detailed processing of step ST12 shown in FIG. As shown in the figure, new reference correlation data is obtained by correcting the reference correlation data stored in the data storage memory 22. Specifically, it is calculated as follows.

  First, the position information acquisition unit 26 acquires the position information of the host vehicle, and the speed information acquisition unit 28 acquires the speed information of the host vehicle (ST30). Thereafter, when the communication destination is another vehicle, the in-vehicle information terminal 20 transmits the position information and speed information of the host vehicle to the partner vehicle (ST31). At the same time, the in-vehicle information terminal 20 transmits a request signal for the position information and speed information of the opponent vehicle.

  And the vehicle-mounted information terminal 20 judges whether the position information and speed information of the other party vehicle were able to be received (ST32). When the position information and speed information of the opponent vehicle cannot be received (ST32: NO), the in-vehicle information terminal 20 repeats this process until it can be received. On the other hand, when the position information and speed information of the partner vehicle can be received (ST32: YES), the distance calculation unit 27 calculates the distance between the host vehicle and the communication destination, and the relative speed calculation unit 29 sets the host vehicle relative to the communication destination. The relative speed is calculated (ST33). Then, the distance calculation unit 27 and the relative speed calculation unit 29 transmit the calculated information to the calculation information acquisition unit 33.

  Thereafter, the building detection unit 31 loads the map information from the map database (ST34). When the memory capacity is limited, the map information to be loaded here may be cut out by the minimum necessary information amount in accordance with the memory capacity. In addition, when there is a sufficient memory capacity, map information of all regions may be loaded.

  After loading, the building detection unit 31 detects scales such as the height, width, and depth of the building (ST35), and transmits scale information and the like to the radio wave arrival estimation unit 32. Then, the radio wave arrival estimation unit 32 maps the own vehicle, the communication destination, the building, and the like on the map (ST36). After mapping, the radio wave arrival estimation unit 32 performs a simulation to determine whether or not the radio wave reaches the communication destination. That is, it is estimated whether or not the radio wave arrives in consideration of radio wave interference and diffraction (ST37). Then, the radio wave arrival estimation unit 32 transmits the estimation result information to the calculation information acquisition unit 33.

  Thereafter, the calculation information acquisition unit 33 transmits the distance information, the relative speed information, and the estimation result information to the frequency calculation unit 23, and the frequency calculation unit 23 corrects the reference correlation data described with reference to FIG. Then, new reference correlation data is calculated (ST38). And a process transfers to step ST13 of FIG.

Reference is again made to FIG. After calculating the new reference correlation data, the frequency calculation unit 23 calculates the frequency to be communicated based on the new reference correlation data (ST13). Then, the communication method selection unit 24 selects any one of the _n radio communication terminals 10 ₁ to 10 _n (ST14). Specifically, when the frequency to be communicated is 2.4 GHz, the communication method selection unit 24 selects the 802.11b or 802.11g wireless communication terminal 10 and the frequency to be communicated is 5.2 GHz. , 802.11a wireless communication terminal 10 is selected.

  Thereafter, the communication method change unit 25 sets the wireless communication terminal 10 selected by the communication method selection unit 24 to a wireless communication enabled state, and sets the wireless communication terminal 10 not selected to a wireless communication disabled state. Then, the in-vehicle information terminal 20 performs wireless communication with the communication destination using the wireless communication terminal 10 in a wireless communication enabled state (ST15). Thereby, communication can be performed by the wireless communication terminal 10 in which the communication speed that is one of the communication qualities is appropriate.

  Thereafter, the process returns to step ST12 and is repeated until, for example, the ignition switch is turned off.

  Thus, according to the vehicle communication device 1 according to the first embodiment, the communication frequency for wireless communication with the communication destination is calculated based on the correlation data between the frequency and the throughput. It is possible to calculate a communication frequency in consideration of the communication speed. Since the wireless communication terminal 10 to be used for wireless communication is selected from the plurality of wireless communication terminals 10 on the basis of the calculated communication frequency, the wireless communication terminal 10 can select a wireless signal suitable for communication speed. The communication terminal 10 can be selected.

  Further, the selected wireless communication terminal 10 is set in a wireless communication enabled state, and the wireless communication terminal 10 that is not selected is set in a wireless communication disabled state. For this reason, among the plurality of wireless communication terminals 10, wireless communication is performed by the wireless communication terminal 10 suitable in terms of communication speed. Accordingly, communication quality can be improved.

  Further, correlation data between the frequency and the throughput is obtained based on the stored information. Here, the throughput varies depending on the traveling environment such as the surrounding environment. Therefore, the correlation data between the frequency and the throughput also varies depending on the driving environment. Therefore, rather than storing only one correlation data between the frequency and the throughput as a fixed one in advance, the frequency and the throughput are set so as to cope with the change of the driving environment based on the stored information. By obtaining new correlation data, the communication frequency can be calculated with high accuracy.

  Further, new reference correlation data is obtained based on the distance correlation data as information stored in advance and the calculated distance. For this reason, appropriate reference correlation data is obtained according to the distance between the host vehicle and the communication destination, and a communication frequency more appropriate in terms of communication quality can be obtained.

  Further, new reference correlation data is obtained based on the velocity correlation data as information stored in advance and the calculated relative velocity. For this reason, appropriate reference correlation data is obtained according to the speed of the host vehicle with respect to the communication destination, and a communication frequency more appropriate in terms of communication quality can be obtained.

  Moreover, it is estimated whether it is communicable with a communication destination from the information of the building as the information memorize | stored previously, and the acquired positional information of the own vehicle and the communication destination, and new reference correlation data is obtained based on the estimation result. . For this reason, appropriate reference correlation data is obtained according to the availability of communication, and a communication frequency more appropriate in terms of communication quality can be obtained.

  Further, since the frequency with the highest throughput is calculated as the communication frequency based on the reference correlation data, the communication speed, which is one of the communication qualities, can be most suitable for wireless communication.

  In this embodiment, distance correlation data, velocity correlation data, map information, and the like are stored, and new reference correlation data is calculated. However, the present invention is not limited to this, and is obtained by performing test communication. The communication frequency may be calculated based on the reference correlation data. In this case, the frequency calculation unit 23 stores data such as a communication frequency when performing test communication as information stored in advance, and obtains new reference correlation data based on the stored data.

Further, it is desirable that at least one of the _n radio communication terminals 10 ₁ to 10 _n is physically and electrically connected to the in-vehicle information terminal 20 in a default state. Thereby, a minimum amount of information can be exchanged in the initial state.

  Next, a second embodiment of the present invention will be described. The vehicle communication device 2 according to the second embodiment is the same as that of the first embodiment, but the configuration of the in-vehicle information terminal 20 and part of the processing contents are different from those of the first embodiment.

  Hereinafter, the vehicle communication device 2 according to the second embodiment will be described. FIG. 10 is a schematic configuration diagram of the vehicle communication device 2 according to the second embodiment. As shown in the figure, the vehicle communication device 2 according to the present embodiment is newly provided with a recommended throughput storage unit (recommended throughput storage means) 34.

  The recommended throughput storage unit 34 stores a recommended throughput for obtaining an amount of information necessary for executing an application. For example, when reproducing a moving image, a throughput of at least about 1 Mbps is required. That is, the recommended throughput storage unit 34 stores information such as “a throughput of 1 Mbps is necessary when reproducing a moving image”.

  The recommended throughput storage unit 34 is connected to the frequency calculation unit 23, and the recommended throughput information is read by the frequency calculation unit 23. For this reason, the frequency calculation unit 23 calculates the communication frequency based on the recommended throughput stored in the recommended throughput storage unit 34 in addition to the reference correlation data.

  Here, the calculation method of the frequency calculation unit 23 will be described in detail. FIG. 11 is an explanatory diagram showing an example of new reference correlation data and recommended throughput. In short, the frequency calculation unit 23 calculates the communication frequency so as to exceed the recommended throughput. The recommended throughput is stored as a certain value as described above. That is, in the example shown in FIG. 11, it is stored as about 7.5 Mbps. Therefore, the frequency calculation unit 23 calculates a frequency exceeding 7.5 Mbps as the communication frequency.

  More specifically, the frequency calculation unit 23 exceeds the recommended throughput but does not exceed the recommended throughput (for example, up to a recommended throughput + α (α is a positive value), or a recommended throughput × β (β is a number exceeding 1). ) To obtain the communication frequency.

  For example, it is assumed that all other vehicles in the vicinity of the host vehicle perform data communication at a communication frequency that can achieve the highest throughput. In this case, the communication band per unit becomes narrow, and as a result, the throughput may be lowered. For this reason, in the second embodiment, the frequency calculation unit 23 obtains the communication frequency so as to ensure the minimum required throughput based on the recommended throughput. Therefore, in the example shown in FIG. 11, when the distance between the host vehicle and the communication destination is 10 m, the frequency calculation unit 23 uses about 2.0 GHz as the communication frequency instead of 5.2 GHz indicating the maximum throughput. Will be asking.

  When the distance between the host vehicle and the communication destination is 20 m, the communication frequency does not exceed about 7.5 Mbps. In this case, the frequency calculation unit 23 changes the type of information for wireless communication so as to exceed the recommended throughput. For example, if a change is made so that a still image is displayed without reproducing a moving image, the recommended throughput is lowered. For example, in the example shown in FIG. 11, if the recommended throughput is lowered from 7.5 Mbps to several Mbps, the 2.4 GHz band exceeds the recommended throughput. Then, the communication frequency is calculated in the same manner as described above from the communication frequencies exceeding the recommended throughput.

  Note that the frequency calculation unit 23 simply calculates the frequency with the highest throughput as the communication frequency without changing the type of information for wireless communication, and notifies the driver that the throughput has not reached the recommended throughput. You may do it.

  Next, an example of detailed operation of the vehicle communication device 2 according to the second embodiment will be described. FIG. 12 is a flowchart illustrating an example of the operation of the vehicle communication device 2 according to the second embodiment. In FIG. 12, the processes shown in steps ST40 to ST42, ST44, and ST45 are the same as the processes shown in steps ST10 to ST12, ST14, and ST15 shown in FIG.

  After calculating new reference correlation data (after ST42), the frequency calculation unit 23 calculates a communication frequency from the new reference correlation data and the recommended throughput (ST43). At this time, the frequency calculation unit 23 calculates the communication frequency as described with reference to FIG.

  And a process will return to step ST42 through step ST44, ST45. Thereafter, for example, the process shown in FIG. 12 is repeated until the ignition switch is turned off.

  Thus, according to the vehicle communication device 2 according to the second embodiment, the communication quality can be improved as in the first embodiment. In addition, the communication frequency can be calculated with high accuracy, and a communication frequency more appropriate in terms of communication quality can be obtained. In addition, in wireless communication, a communication speed that is one of communication qualities can be made most suitable.

  Furthermore, according to the second embodiment, the communication frequency is calculated based on the recommended throughput for obtaining the information amount necessary for executing the application in addition to the reference correlation data. Here, if data communication is performed at a communication frequency at which all other vehicles in the vicinity of the vehicle can achieve the highest throughput, the communication band per unit becomes narrow, and as a result, the throughput may be lowered. is there. However, in the second embodiment, the communication frequency is obtained so that the minimum required throughput is ensured based on the recommended throughput, so the communication band per unit is unlikely to be narrowed, and communication quality can be improved. it can.

  Next, a third embodiment of the present invention will be described. The vehicle communication device 3 according to the third embodiment is the same as that of the first embodiment, but the configuration of the in-vehicle information terminal 20 and a part of the processing content are different from those of the first embodiment.

  Hereinafter, the vehicle communication device 3 according to the third embodiment will be described. FIG. 13 is a schematic configuration diagram of the vehicle communication device 3 according to the third embodiment. As shown in the figure, the vehicular communication device 3 according to the present embodiment includes a new leader vehicle determination unit (leader vehicle determination means) 35 and an organizer identification unit (organizer identification) as the configuration of the in-vehicle information terminal 20. Means) 36, a traveling environment recognition unit (traveling environment recognition unit) 37, and a timing calculation unit 38.

The leader vehicle determination unit 35 determines a leader vehicle from a plurality of vehicles. Here, the leader vehicle refers to a vehicle that determines not only the communication frequency of the host vehicle but also the communication frequency of other vehicles. That is, a vehicle that has not become a leader vehicle selects one to be used for communication from the _n radio communication terminals 10 ₁ to 10 _n according to the communication frequency instructed by the leader vehicle.

  The leader vehicle determination unit 35 is connected to the position information acquisition unit 26. For this reason, the leader vehicle determination unit 35 acquires the position information of the host vehicle and other vehicles from the position information acquisition unit 26, and determines, as the leader vehicle, a leading vehicle that travels at the head of the vehicle group including a plurality of vehicles. It will be. In addition, the leader vehicle determination unit 35 may determine not only the leading vehicle but also the last vehicle that travels at the tail of the vehicle group and the central vehicle that travels near the center of the vehicle group as the leader vehicle.

  The leader vehicle determination unit 35 is connected to the communication method selection unit 24. For this reason, the communication method selection part 24 will judge whether the radio | wireless communication terminal 10 which should be used for communication is determined based on whether the own vehicle became a leader vehicle. That is, when the own vehicle is a leader vehicle, the communication method selection unit 24 calculates the communication frequency in the own vehicle and selects the wireless communication terminal 10. When the own vehicle is not the leader vehicle, the communication method selection unit 24 transmits from the leader vehicle. The wireless communication terminal 10 is selected based on the communication frequency.

  The organizer specifying unit 36 specifies a drive organizer based on information on mail transmission / reception between the vehicles. Further, the organizer specifying unit 36 is connected to the leader vehicle determining unit 35. For this reason, the leader vehicle determination unit 35 is also configured to determine the vehicle on which the drive organizer specified by the organizer specifying unit 36 is a leader vehicle.

  The travel environment recognition unit 37 recognizes the travel environment around the host vehicle. In addition, the timing calculation unit 38 inputs information on the travel environment recognized by the travel environment recognition unit 37 and obtains a timing at which the driving load increases.

  Further, the timing calculation unit 38 is connected to the communication method change unit 25. For this reason, the communication method change unit 25 of the third embodiment allows the wireless communication terminal 10 to be in a wireless communication enabled state and a wireless communication disabled state at the timing calculated by the timing calculating unit 38 (the timing at which the driving load increases). It is supposed to be.

  Furthermore, when the host vehicle is a leader vehicle, the timing calculation unit 38 controls the timing of transmitting communication frequency information to other vehicles. That is, the timing calculation unit 38 controls the in-vehicle information terminal 20 to transmit information on the communication frequency to other vehicles at a timing when the driving load increases.

  Next, an outline of the operation of the vehicle communication device 3 according to the third embodiment will be described. First, in the vehicle communication device 3, the leader vehicle determination unit 35 determines the leader vehicle based on the information from the position information acquisition unit 26 or the drive organizer information specified by the organizer specification unit 36. To do.

  FIG. 14 is a diagram illustrating processing when the leader vehicle determination unit 35 determines a leader vehicle based on information from the position information acquisition unit 26, and (a) illustrates a case where the leading vehicle is determined as the leader vehicle. (B) shows the case where the last vehicle is determined as the leader vehicle, and (c) shows the case where the central vehicle is determined as the leader vehicle.

  As shown in the figure, the vehicle group is composed of four vehicles 101 to 104, and the coordinates of each vehicle are (x1, y1) (x2, y2) (x3, y3) (x4, y4). Suppose that

  When the leading vehicle is determined to be the leader vehicle, the leader vehicle determining unit 35 identifies the leading vehicle with the smallest coordinate value on the x-axis as shown in FIG. To do.

  Further, when determining the last vehicle as the leader vehicle, the leader vehicle determination unit 35 identifies the one having the largest coordinate value on the x-axis as the last vehicle, as shown in FIG. And decide.

  Further, when the central vehicle is determined as the leader vehicle, the leader vehicle determination unit 35 obtains the coordinate value (xg, yg) of the center of gravity from each coordinate value, as shown in FIG. And the vehicle which exists in the position nearest to the coordinate value (xg, yg) of the center of gravity is specified as the central vehicle and determined as the leader vehicle.

  When the leader vehicle determination unit 35 determines the leader vehicle based on the information of the drive organizer specified by the organizer specification unit 36, for example, the drive organizer is specified as follows, and the leader vehicle is determined. It is determined.

  In other words, suppose that by the day the drive is performed, someone in the group has sent an email or the like of the drive to those who want to participate in the drive. In this case, the organizer specifying unit 36 acquires transmission / reception information of the mail and specifies the drive organizer from the address of the transmission source.

  Thereafter, the organizer specifying unit 36 specifies the leader vehicle based on the specified drive organizer. At this time, the organizer specifying unit 36 stores, for example, a mail address stored in advance and vehicle information in association with each other, and determines a leader vehicle based on the vehicle information. Moreover, you may make it determine a leader vehicle based on an IP address.

  Then, the leader vehicle determination unit 35 transmits information on the leader vehicle determined as described above to the communication method selection unit 24. Here, when the leader vehicle is the host vehicle, the frequency calculation unit 23 obtains the communication frequency based on the signals from the units 22 to 33 described above. Then, the communication method selection unit 24 selects the wireless communication terminal 10 to be used for wireless communication based on the communication frequency calculated by the frequency calculation unit 23.

  When the leader vehicle is the host vehicle, the traveling environment recognition unit 37 starts recognition of the traveling environment. Thereafter, the timing calculation unit 38 obtains a timing at which the driving load increases. And the vehicle-mounted information terminal 20 transmits the information of the calculated communication frequency to another vehicle in the timing when the driving load calculated | required by the timing calculation part 38 becomes high.

  Then, after the transmission, the communication method change unit 25 sets the wireless communication terminal 10 selected by the communication method selection unit 24 in a communicable state, and sets the wireless communication terminal 10 not selected in a communication disabled state.

  On the other hand, when the leader vehicle is not the host vehicle, the frequency calculation unit 23 does not obtain the communication frequency, and the communication method selection unit 24 does not select the wireless communication terminal 10 to be used for wireless communication. That is, the communication method selection unit 24 is in a standby state until the communication frequency information is transmitted from the leader vehicle, and selects the wireless communication terminal 10 to be used for wireless communication based on the transmitted information.

  As described above, it is possible to improve communication quality while ensuring a comfortable communication state. That is, if each vehicle changes the communication frequency disparately, the communication frequency cannot be unified, and the wireless communication is inhibited. However, in the third embodiment, since the leader vehicle calculates the communication frequency and transmits it to each vehicle, the communication frequency can be unified.

  In addition, since the wireless communication terminal 10 is changed at a timing when the driving load increases, it is difficult for the driver to recognize the change of the wireless communication terminal 10. That is, when the driving load is high, it is difficult for the driver to recognize the change of the wireless communication terminal 10, and even if the data communication is temporarily suspended due to the change of the wireless communication terminal 10, the comfort is not impaired. It has become.

  Next, an example of detailed operation of the vehicle communication device 3 according to the third embodiment will be described. FIG. 15 is a flowchart illustrating an example of the operation of the vehicle communication device 3 according to the third embodiment. As shown in the figure, first, the in-vehicle information terminal 20 determines whether or not it is necessary to change the communication frequency (ST50). For example, when the number of vehicles increases at junctions and intersections, when radio waves are blocked by buildings such as buildings, communication is impossible, and when the content to be acquired and the application to be executed are changed, The in-vehicle information terminal 20 determines that the communication frequency needs to be changed.

  When it is determined that the communication frequency needs to be changed (ST50: YES), the in-vehicle information terminal 20 determines whether to determine the leader vehicle from the positional relationship (ST51). When it is determined that the leader vehicle is determined from the positional relationship (ST51: YES), the leader vehicle determination unit 35 determines the leader vehicle based on the position information (ST52).

  FIG. 16 is a flowchart showing detailed processing of step ST52 shown in FIG. In the example shown in FIG. 14, the leader vehicle is determined from the coordinate value of each vehicle, but in FIG. 16, the leader vehicle is determined from the distance between the vehicles.

  As shown in the figure, when the leader vehicle is determined based on the position information, first, the position information acquisition unit 26 acquires the position information of the own vehicle (ST60). Thereafter, the in-vehicle information terminal 20 transmits the position information of the host vehicle to the partner vehicle (ST61). At the same time, the in-vehicle information terminal 20 transmits a request signal for position information of the opponent vehicle.

  And the vehicle-mounted information terminal 20 judges whether the positional information on the other party vehicle was able to be received (ST62). When the position information of the partner vehicle cannot be received (ST62: NO), the in-vehicle information terminal 20 repeats this process until it can be received. On the other hand, when the position information of the partner vehicle can be received (ST62: YES), the distance calculation unit 27 calculates the distance between the host vehicle and the partner vehicle (ST63). Then, the distance calculation unit 27 transmits the calculated information to the leader vehicle determination unit 35.

  Thereafter, the leader vehicle determination unit 35 determines the leader vehicle based on the distance information calculated by the distance calculation unit 27 (ST64). At this time, for example, the leader vehicle determination unit 35 specifies the leading vehicle, the last vehicle, or the central vehicle from the distance relationship with the own vehicle, and determines the leader vehicle. After the determination, the process proceeds to step ST54 shown in FIG.

  By the way, when it is determined in step ST51 that the leader vehicle is not determined from the positional relationship (ST51: NO), the leader vehicle determination unit 35 determines the leader vehicle based on the organizer of the drive (ST53).

  FIG. 17 is a flowchart showing detailed processing of step ST53 shown in FIG. As shown in the figure, when the leader vehicle is determined based on the drive organizer, the organizer specifying unit 36 first checks the current date and time from a GPS signal or the like (ST70). Thereafter, the organizer specifying unit 36 initializes the variable i to “1” (ST71).

  Then, the organizer specifying unit 36 refers to the i-th mail that is held (ST72). Specifically, the organizer specifying unit 36 refers to the reception (transmission) date and time, the subject, and the transmission source in the i-th mail.

  Thereafter, the organizer specifying unit 36 determines whether or not the date and time of the drive holding mail matches the current date and time (ST73). Here, the date and time of the drive opening email can be determined from the date of reception (transmission) of the email, and the current date and time can be determined from the time information acquired in step ST70. Note that, in step ST73, the coincidence determination is made with a certain amount of time, and a slight time shift is allowed.

  Here, when it is determined that the date / time of the drive held mail does not match the current date / time (ST73: NO), the organizer specifying unit 36 increments the variable i (ST74), and refers to the mail again in step ST72. Will be performed.

  On the other hand, when it is determined that the date / time of the drive held mail matches the current date / time (ST73: YES), the organizer specifying unit 36 determines whether the drive held mail conforms to a prescribed format (ST75). ). For example, the organizer specifying unit 36 determines whether or not the subject includes the word “[Drive]” in the first place, such as “[Drive]”, and whether or not it conforms to the prescribed format. Will be judged.

  Here, if it is determined that the mail held by the drive does not conform to the prescribed format (ST75: NO), the organizer specifying unit 36 increments the variable i (ST74), and again refers to the mail in step ST72. Will be done.

  On the other hand, if it is determined that the email for driving is in compliance with the prescribed format (ST75: YES), the organizer specifying unit 36 recognizes the transmission source (drive organizer) (ST76). Then, the organizer specifying unit 36 transmits the information of the recognized drive organizer to the leader vehicle determining unit 35. The leader vehicle determination unit 35 determines a leader vehicle based on the information from the organizer identification unit 36 (ST77). And a process transfers to step ST54 of FIG.

  In step ST54, the traveling environment recognition unit 37 recognizes the current traveling environment (ST54). Then, the travel environment recognition unit 37 transmits the recognized travel environment information to the timing calculation unit 38.

  Thereafter, the timing calculation unit 38 determines whether or not the current driving load is high from information on the traveling environment (ST55). Here, the driving load is high, for example, when the vehicle speed is high, when the vehicle is in an intersection, during merging, while turning a curve, or when the weather is bad.

  If it is determined that the driving load is not high (ST55: NO), the process returns to step ST54, and the determination of whether the driving environment is recognized and whether the driving load is high is repeated.

On the other hand, when it is determined that the driving load is high (ST55: YES), the communication method of the host vehicle and the opponent vehicle is changed by the leader vehicle (ST56). That is, the leader vehicle obtains a communication frequency in its own vehicle, selects and changes the state of the wireless communication terminal 10 to be used for communication from the _n wireless communication terminals 10 ₁ to 10 _n according to the obtained communication frequency, and performs communication. Send frequency information to other vehicles. A vehicle that has not become a leader vehicle determines what should be used for communication from _n radio communication terminals 10 ₁ to 10 _n according to the communication frequency instructed by the leader vehicle, and changes its state. Note that the leader vehicle transmits information by adding information on how many seconds (minutes) the change is made to the communication frequency information.

  Thereafter, the in-vehicle information terminal 20 performs wireless communication with another vehicle using the wireless communication terminal 10 in a wireless communication enabled state (ST57). As a result, communication quality is improved while ensuring a comfortable communication state.

  Then, the process returns to step ST50. If it is determined in step ST50 that there is no need to change the communication frequency (ST50: NO), the in-vehicle information terminal 20 performs wireless communication with another vehicle without changing the communication frequency ( ST57).

  In this way, according to the vehicle communication device 3 according to the third embodiment, it is possible to improve the communication quality as in the first embodiment. In addition, the communication frequency can be calculated with high accuracy, and a communication frequency more appropriate in terms of communication quality can be obtained. In addition, in wireless communication, a communication speed that is one of communication qualities can be made most suitable.

  Furthermore, according to the third embodiment, the leader vehicle calculates the communication frequency, selects the wireless communication terminal 10 to be used for wireless communication, and transmits information on the communication frequency to each vehicle. And the vehicle which is not a leader vehicle has selected the radio | wireless communication terminal 10 which should be used for radio | wireless communication according to the communication frequency transmitted from the leader vehicle. For this reason, the communication frequency is unified, and each vehicle changes the communication frequency in a different manner, so that the communication frequency cannot be unified and wireless communication is not hindered. Therefore, it is possible to improve communication quality while ensuring a comfortable communication state.

  Further, since the leading vehicle, the last vehicle, or the central vehicle is determined as the leader vehicle, when the leading vehicle or the last vehicle is determined as the leader vehicle, the vehicle located at the end of the vehicle group, that is, the most radio wave environment The communication frequency can be changed based on a bad vehicle. Further, when the central vehicle is determined as the leader vehicle, the communication frequency can be changed with reference to a vehicle located in the center of the vehicle group, that is, a vehicle whose radio wave environment is an average in the vehicle group.

  In addition, the leader of the drive is determined by judging the organizer of the drive from a drive holding mail or the like. For this reason, the leader vehicle is fixed regardless of the surrounding environment or the like, and the processing load can be reduced when the communication frequency is changed.

  Further, since the communication frequency is changed at the timing when the driving load increases, it is difficult for the driver to recognize the change of the wireless communication terminal 10 used for wireless communication. Therefore, comfort is not impaired.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not restricted to the said embodiment, You may combine each embodiment. Moreover, you may add a change in the range which does not deviate from the meaning of this invention.

1 is a schematic configuration diagram of a vehicle communication device according to a first embodiment. It is explanatory drawing which shows an example of the correlation data of a frequency and a throughput. It is explanatory drawing which shows an example of distance correlation data. It is explanatory drawing which shows an example of the estimation method by a radio wave arrival estimation part. It is explanatory drawing which shows an example of the new reference | standard correlation data calculated | required using distance correlation data. It is explanatory drawing which shows an example of the new reference | standard correlation data calculated | required using speed correlation data. It is a flowchart which shows an example of operation | movement of the vehicle communication apparatus which concerns on 1st Embodiment. It is a flowchart which shows the detailed process of step ST10 shown in FIG. It is a flowchart which shows the detailed process of step ST12 shown in FIG. It is a schematic block diagram of the vehicle communication apparatus which concerns on 2nd Embodiment. It is explanatory drawing which shows an example of new reference | standard correlation data and a recommended throughput. It is a flowchart which shows an example of operation | movement of the communication apparatus for vehicles which concerns on 2nd Embodiment. It is a schematic block diagram of the vehicle communication apparatus which concerns on 3rd Embodiment. It is a figure explaining the process in case a leader vehicle determination part determines a leader vehicle based on the information from a positional information acquisition part, (a) shows the case where a leading vehicle is determined as a leader vehicle, (b) Indicates the case where the last vehicle is determined as the leader vehicle, and (c) indicates the case where the central vehicle is determined as the leader vehicle. It is a flowchart which shows an example of operation | movement of the vehicle communication apparatus which concerns on 3rd Embodiment. It is a flowchart which shows the detailed process of step ST52 shown in FIG. It is a flowchart which shows the detailed process of step ST53 shown in FIG.

Explanation of symbols

1 to 3 ... Vehicle communication devices 10 ₁ to 10 _n ... Wireless communication terminals (wireless communication means)
20 ... In-vehicle information terminal 23 ... Frequency calculation unit (frequency calculation means)
24. Communication method selection unit (selection means)
25 ... Communication system changing unit (state changing means)
26: Position information acquisition unit (position information acquisition means)
27: Distance calculation unit (distance calculation means)
28 ... Speed information acquisition unit (speed information acquisition means)
29 ... Relative speed calculation unit (relative speed calculation means)
30 ... Map database (map storage means)
32 ... Radio wave arrival estimation unit (communication availability estimation means)
34 ... Recommended throughput storage unit (throughput storage means)
35 ... Leader vehicle determining unit (leader vehicle determining means)
36 ... Organizer identification part (Organizer identification means)
37. Driving environment recognition unit (driving environment recognition means)

Claims (9)

In the vehicle communication device that is mounted on the host vehicle and communicates wirelessly with the communication destination,
A plurality of wireless communication means capable of wireless communication with a communication destination in different frequency bands,
Based on correlation data between the frequency and the throughput, a frequency calculation means for calculating a communication frequency when performing wireless communication with the communication destination,
Selection means for selecting a wireless communication means to be used for wireless communication from the plurality of wireless communication means based on the communication frequency calculated by the frequency calculation means;
A state changing unit that sets the wireless communication unit selected by the selection unit to a wireless communication enabled state, and sets the wireless communication unit that is not selected to a wireless communication disabled state;
Position information acquisition means for acquiring the position information of the host vehicle and the position information of the communication destination;
Distance calculating means for calculating the distance between the two based on the position information of the host vehicle and the position information of the communication destination acquired by the position information acquiring means,
The frequency calculating means obtains correlation data between the frequency and the throughput based on the distance calculated by the distance calculating means and the correlation data between the distance and the throughput, which is information stored in advance. Communication equipment. In the vehicle communication device that is mounted on the host vehicle and communicates wirelessly with the communication destination,
A plurality of wireless communication means capable of wireless communication with a communication destination in different frequency bands,
Based on correlation data between the frequency and the throughput, a frequency calculation means for calculating a communication frequency when performing wireless communication with the communication destination,
Selection means for selecting a wireless communication means to be used for wireless communication from the plurality of wireless communication means based on the communication frequency calculated by the frequency calculation means;
A state changing unit that sets the wireless communication unit selected by the selection unit to a wireless communication enabled state, and sets the wireless communication unit that is not selected to a wireless communication disabled state;
Speed information acquisition means for acquiring the speed of the host vehicle and the speed of the communication destination;
Relative speed calculation means for calculating the relative speed of the host vehicle with respect to the communication destination based on the speed of the host vehicle and the speed of the communication destination acquired by the speed information acquisition means,
The frequency calculation means obtains correlation data between the frequency and the throughput based on the relative speed calculated by the relative speed calculation means and the correlation data between the speed and the throughput, which is information stored in advance. A vehicle communication device. In the vehicle communication device that is mounted on the host vehicle and communicates wirelessly with the communication destination,
A plurality of wireless communication means capable of wireless communication with a communication destination in different frequency bands,
Based on correlation data between the frequency and the throughput, a frequency calculation means for calculating a communication frequency when performing wireless communication with the communication destination,
Selection means for selecting a wireless communication means to be used for wireless communication from the plurality of wireless communication means based on the communication frequency calculated by the frequency calculation means;
A state changing unit that sets the wireless communication unit selected by the selection unit to a wireless communication enabled state, and sets the wireless communication unit that is not selected to a wireless communication disabled state;
Position information acquisition means for acquiring the position information of the host vehicle and the position information of the communication destination;
Map storage means storing at least information on buildings;
Based on the position information of the own vehicle and the position information of the communication destination acquired by the position information acquisition means, and the building information stored by the map storage means, wireless communication between the own vehicle and the communication destination is possible. Communication availability estimation means for estimating whether or not,
The vehicle communication apparatus , wherein the frequency calculation means obtains correlation data between the frequency and the throughput based on an estimation result by the communication availability estimation means . The frequency calculation means calculates a frequency having the highest throughput as the communication frequency based on correlation data between the frequency and the throughput.
The vehicular communication device according to any one of claims 1 to 3 . A recommended throughput storage means for storing a recommended throughput for obtaining an amount of information necessary for executing the application;
The frequency calculation means calculates the communication frequency based on the recommended throughput stored by the recommended throughput storage means in addition to the correlation data between the frequency and the throughput.
The vehicular communication device according to any one of claims 1 to 3 . A leader vehicle determining means for determining a leader vehicle from a plurality of vehicles;
When the own vehicle is determined to be the leader vehicle by the leader vehicle determining means, the communication frequency information calculated by the frequency calculating means is transmitted to another vehicle, based on the communication frequency calculated by the frequency calculating means, Select a wireless communication means to be used for wireless communication from the plurality of wireless communication means,
When the own vehicle is not determined to be the leader vehicle by the leader vehicle determination means, the plurality of the plurality of the plurality of the plurality of the plurality of the plurality of times are determined based on the communication frequency information transmitted from the leader vehicle without being based on the communication frequency calculated by the frequency calculation means Select wireless communication means to be used for wireless communication from wireless communication means
The vehicular communication device according to any one of claims 1 to 3 . It further comprises position information acquisition means for acquiring position information of each of the plurality of vehicles,
The leader vehicle determining means is based on the position information of each of the plurality of vehicles acquired by the position information acquiring means, the leading vehicle that travels at the head of the group of the plurality of vehicles, and the last tail that travels at the tail. The vehicle communication device according to claim 6 , wherein any one of the vehicle and a central vehicle traveling near the center is identified and determined as a leader vehicle . Further comprising an organizer identifying means for identifying a drive organizer based on information of transmission / reception of mail between vehicles,
The vehicle communication device according to claim 6 , wherein the leader vehicle determining means determines the leader vehicle based on information of the drive organizer specified by the organizer specifying means . The vehicle further comprises driving environment recognition means for recognizing the driving environment,
When the own vehicle is determined to be a leader vehicle by the leader vehicle determining means, and the traveling environment recognized by the traveling environment recognizing means has a high driving load, it is calculated by the frequency calculating means. transmits the information of the communication frequency to another vehicle, and the wireless communication means and the selected wireless communication state, the claims 6-8, characterized in that the wireless communication means that are not selected as the wireless communication disabled state The vehicle communication device according to claim 1.

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