JPH11146464A - Ground communication device, in-vehicle communication device, and road-vehicle data communication system - Google Patents

Abstract

(57) [Problem] Since a vehicle cannot receive a large amount of data from one beacon, when the vehicle exits the communication area of the beacon and enters the communication area of another beacon,
When the remaining data is divided and acquired, the communication is executed by specifying "another beacon" where the vehicle is expected to run. When a beacon communication device determines that data cannot be transmitted to an on-vehicle communication device at a time, it is expected that the vehicle will continue to travel along a road in the traveling direction, The other beacon communication device 1 on the road along the traveling direction is specified, and information for specifying the remaining data is transmitted to this "other beacon communication device 1".

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of terrestrial communication devices, and a terrestrial communication device that receives a data transmission request from an on-vehicle communication device accesses a database to acquire necessary data, and transmits the data to a vehicle. The present invention relates to a road-vehicle data communication system provided to a communication device.

[0002]

2. Description of the Related Art In a road-to-vehicle data communication system, data communication is performed between a terrestrial communication device (such as a broadcasting station and a beacon; hereinafter, typically referred to as a "beacon") and a vehicle-mounted communication device mounted on a vehicle. It is a method.

In the road-to-vehicle data communication system, the time at which communication with one beacon can be performed is limited because the vehicle is moving at a certain speed. For example, the vehicle speed is 70 km / h, the communication area of the optical beacon is 3.5 m,
Downlink (beacon to vehicle) communication speed of 1.0
24 Mbit / s, uplink (beacon from vehicle)
If the communication speed of the vehicle is 64 kbit / sec, the amount of data that can be received by the vehicle-mounted communication device when the vehicle is passing under one beacon is only about 80 kbytes.

Therefore, when receiving data (eg, road map data, moving image data, etc.) larger than 80 kbytes, it is conceivable to transmit the data by dividing it from a plurality of beacons. The following can be considered as the procedure. When the vehicle enters the communication area of the first beacon (referred to as “beacon 1”), the vehicle-mounted communication device
A data transfer request is issued to the beacon 1. The beacon 1 retrieves data by searching a database which is a fixed host, and starts transferring data. Data transfer is interrupted when the vehicle exits the communication area of the beacon 1. The in-vehicle communication device checks the data received so far, and issues a transfer request for the remaining data not received at this time when the vehicle enters the communication area of the next beacon (referred to as “beacon 2”). . The beacon 2 retrieves a database serving as a fixed host, extracts remaining data, and transfers the data to the in-vehicle communication device. Data transfer is interrupted when the vehicle leaves the communication area of the beacon 2. When the vehicle enters the communication area of the next beacon (referred to as "beacon 3"), the same is repeated.

[0005]

In the above data transfer procedure, in addition to connecting the communication line between the vehicle and the beacon every time the vehicle enters the communication area of the beacon, the data transfer procedure between the beacon and the database is performed. Since an operation of connecting a communication line and an operation of transmitting data are required, the substantial communication time is further reduced, and the amount of data that the in-vehicle communication device can receive is reduced.

Therefore, if the next beacon can be specified when the vehicle leaves the communication area of the beacon, the remaining data is transferred to the next beacon in advance, thereby newly establishing a communication line between the beacon and the database. The time for connecting and transmitting data can be saved.

[0007] However, in practice, it is not known which beacon communication area the moving vehicle will enter next. For this reason,
Yawata et al. Proposed a method of transmitting the remaining data to all beacons adjacent to the current communication area using a geographical radiation method (Yawata et al., "Architecture for Continuous Media" Symposium "Mobile & Ubiquitous Computing" pp.81-8
8, 1995.7.26-28).

However, in this method, the remaining data must be transferred to all the beacons adjacent to the current communication area. Therefore, there is a need for a road-to-vehicle data communication system capable of efficiently acquiring the remaining data when a vehicle identifies a beacon to pass next and enters the communication area of the next beacon.

Further, all data can be exchanged while the data amount is small and the vehicle is in the beacon communication area, or all data can be exchanged while the data amount is large and the vehicle is in the beacon communication area. Regardless of the case where communication is not possible, if the route on which the vehicle travels is known and the necessary data can be transferred to the beacon at the end of the route in a timely manner, the vehicle is required when necessary Data can be received,
There is a need for a road-to-vehicle data communication system that can transfer such data because it leads to more efficient communication.

[0010]

A terrestrial communication apparatus used in the road-to-vehicle data communication system according to the present invention comprises a traveling direction obtaining means for knowing the traveling direction of a vehicle, and a series of data amounts to be transmitted to the on-vehicle communication apparatus. The data amount estimating means for estimating, and when it is determined that all the data cannot be transmitted to the on-vehicle communication device, based on the traveling direction of the vehicle, the untransmitted data is transmitted to another ground communication device which the vehicle is expected to pass next. And a not-yet-transmitted data notifying means for notifying the information for specifying the data of (1).

According to this ground communication device, when it is determined that data cannot be transmitted to the on-vehicle communication device at one time, the vehicle is expected to continue traveling along the road in the traveling direction. The other ground communication device on the road along the traveling direction can be specified, and the data can be divided and transmitted together with the “other ground communication device”.

The vehicle-mounted communication device used in the road-to-vehicle data communication system of the present invention has a traveling direction transmitting means for knowing the traveling direction of the vehicle and transmitting data of the traveling direction to the ground communication device. ). The traveling direction of the own vehicle is acquired on the vehicle side and transmitted to the ground communication device.

The ground communication apparatus used in the road-to-vehicle data communication system according to the present invention is the ground communication apparatus according to claim 1, further comprising a traveling speed acquisition means for knowing a traveling speed of the vehicle, wherein said traveling speed acquisition means. In consideration of the traveling speed of the vehicle acquired by the above, it is determined whether or not all data can be transmitted to the on-vehicle communication device (claim 3).

According to this terrestrial communication apparatus, the traveling speed of the vehicle is taken into consideration in determining whether all data can be transmitted to the on-vehicle communication apparatus. This is because the time during which the vehicle stays in the communication area of the ground communication device differs depending on the traveling speed of the vehicle.

An on-vehicle communication device used in the road-to-vehicle data communication system of the present invention knows the traveling direction of the own vehicle, and transmits traveling direction data to the ground communication device; A traveling speed transmitting means for knowing the traveling speed and transmitting the traveling speed data to the ground communication device; The traveling direction and the traveling speed of the own vehicle are acquired on the vehicle side and transmitted to the ground communication device.

The ground communication device used in the road-to-vehicle data communication system according to the present invention includes a scheduled traveling route acquisition means for knowing a scheduled traveling route of the vehicle, and a data amount estimating device for estimating a series of data amounts to be transmitted to the vehicle-mounted communication device. Means, and when it is determined that all the data cannot be transmitted to the on-vehicle communication device, the untransmitted data is transmitted to another ground communication device on which the vehicle is expected to pass next, based on the travel route of the vehicle. And a not-yet-transmitted data notifying unit for notifying the information to be specified.

According to this terrestrial communication device, when it is determined that data cannot be transmitted to the on-vehicle communication device at one time, the vehicle is expected to continue traveling along the scheduled traveling route. The other terrestrial communication device on the road along the route can be specified, and the data can be divided and transmitted together with the “other terrestrial communication device”.

The on-vehicle communication device used in the road-to-vehicle data communication system of the present invention has a scheduled traveling route transmitting means for transmitting data of the scheduled traveling route of the own vehicle to the ground communication device. When the planned traveling route of the own vehicle is known, the planned traveling route is transmitted to the ground communication device.

An unsent data transfer unit for transferring unsent data itself to another terrestrial communication apparatus may be provided together with or in place of the unsent data notification unit. ). According to this, other terrestrial communication devices do not need to access and acquire the untransmitted data to the database, and the database is not burdened.

Further, according to the road-to-vehicle data communication system of the present invention, the ground communication device includes a traveling route acquisition means for knowing the traveling route of the vehicle, and a traveling device for notifying the information holding device of the traveling route of the vehicle. Scheduled route notification means,
The information holding device has data transfer means for transferring data to another ground communication device that the vehicle is expected to pass next based on the notified travel schedule route (claim 8).

Further, the on-vehicle communication device of the present invention has a transmission means such as a scheduled traveling route for transmitting data of the scheduled traveling route and the scheduled passage time of the own vehicle to the ground communication device.

According to this system, the traveling route of the vehicle can be known, so that the information holding device transfers necessary data to another ground communication device that the vehicle is expected to pass next. Can be.

The information holding device includes time prediction means for predicting a time at which the vehicle will enter a communication area of another terrestrial communication device which is expected to pass next. The data is transferred to the other terrestrial communication device at the timing, and the terrestrial communication device has storage means for temporarily storing the transferred data, and deletes the storage in the storage means when the vehicle leaves the communication area. (Claim 10).

With this system configuration, the time for retaining data in the storage means of the terrestrial communication device can be minimized, and the storage capacity can be minimized.

The "timing immediately before the predicted time"
Can be determined in consideration of the time required from when the terrestrial communication device receives data transfer to when transmission to the vehicle starts.

The information holding device includes a time prediction unit for predicting a time at which the vehicle will enter a communication area of another ground communication device which is expected to pass next, and the vehicle communicates with the other ground communication device. Communication band reservation means for reserving a communication band at the time of entering the area, wherein the untransmitted data transfer means comprises:
The data may be transferred to the other ground communication device at the predicted time (claim 11). With this system configuration, the communication band at the time when the vehicle enters the communication area of the ground communication device can be reserved, so if the untransmitted data transfer means transfers the data at the predicted time, the data is transmitted to the vehicle as it is. can do. Therefore, it is not necessary to provide data storage means in the ground communication device, and the configuration of the ground communication device can be simplified.

In this system, if there are a plurality of vehicles that pass through the communication area of the same ground communication device at the same time, the same communication band can be reserved redundantly (claim 12). Can transmit data to a plurality of vehicles at once.

The in-vehicle communication device is different from the terrestrial communication device in that
It is preferable to request transmission of data related to a route from another terrestrial communication device that the vehicle is scheduled to pass next to yet another terrestrial communication device that is scheduled to pass next (claim 13). .

In this system, the on-vehicle communication device is:
Rather than requesting related data along the route to the destination at once, but requesting them in pieces for each section where the terrestrial communication device is installed, it is possible to reduce the amount of data transmitted per time.

[0030]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a road-vehicle data communication system for providing road map information, traffic information, and the like to a vehicle-mounted communication device mounted on a vehicle.

The road-to-vehicle data communication system includes a beacon communication device 1 installed in a predetermined area along a road.
And a database server 4 connected to the beacon communication device 1 via the communication line 3.

The database server 4 stores the latest information,
For example, information such as road map information, traffic information including traffic congestion information, accident / construction information, road regulation information, and weather forecast information are stored.

The road map information is composed of a link unit which is a vector connecting nodes which are coordinate positions for specifying intersections and bends of roads. The coordinates of the start node and the end node of each link and the coordinates of each link are set. It is stored as data such as an azimuth and a link number. The traffic information and the like are stored as data such as link numbers corresponding to traffic jams and roads subject to regulation.

As shown in FIG. 2, the beacon communication device 1 includes a transceiver 5 for communicating with the on-vehicle communication device 9 via radio waves.
(It may be a light emitter / receiver that communicates with the in-vehicle communication device 9 via light. The same applies to the following.) A processing circuit 6 for processing and transferring data, and a transmission terminal connected to a communication line are provided. When receiving the vehicle identification data and the current position data, the processing circuit 6 transfers the data of the current position and the like to the database server 4 via the communication line 3.

It is not essential to transmit the identification data and the current position data from the vehicle. For example, if a camera is provided in addition to the beacon communication device 1 so as to read the characteristics (eg, plate number) of the vehicle, the identification data may be transmitted. Is no longer required. Further, if the installation position of the beacon communication device 1 is regarded as the current position of the vehicle, the transmission of the current position data of the vehicle becomes unnecessary. However, in the following description, it is assumed that identification data and current position data are transmitted from the vehicle. When the database server 4 receives the current position data of the vehicle from the beacon communication device 1 via the communication line 3, the database server 4 searches for road map information, traffic information, and the like related to the current position, and receives the data via the same communication line 3. And returns it to the beacon communication device 1.

The beacon communication device 1 transmits these data to the communication device mounted on the vehicle.

FIG. 3 is a block diagram showing the electrical configuration of the vehicle-mounted communication device 9 mounted on the vehicle for transmitting and receiving various data to and from the beacon communication device 1.

The vehicle-mounted communication device 9 has a GPS (Global Pos
itioning System) G for receiving signals from satellites
A PS antenna 10 and a GPS receiver 11 are provided. The GPS receiver 11 calculates the current position and azimuth of the vehicle based on the propagation time difference between transmission signals of a plurality of GPS satellites input from the GPS antenna 10. The calculation of the current position and azimuth of the vehicle is repeated at regular intervals (for example, every one second).

Note that, instead of the GPS receiver 11,
The current position and the direction of the vehicle may be detected based on the outputs of the direction sensor and the vehicle speed sensor that detect the amount of change in the direction of the vehicle. More specifically, the traveling direction of the vehicle is determined based on the output of the direction sensor, the traveling distance of the vehicle is determined based on the output of the vehicle speed sensor, and the traveling direction of the vehicle is set at a preset initial position of the vehicle. And the running distance are accumulated to calculate the current position of the vehicle. In this case, it is preferable to perform the map matching using the road map data for detecting the current position stored in the road map database 14.

The in-vehicle communication device 9 further includes a transceiver 13 for transmitting and receiving to and from the beacon communication device 1, and a processing circuit 15. This transmission / reception is performed automatically or when the vehicle enters the communication area of the beacon, automatically or on condition that an information request key (not shown) is operated by a driver or a passenger.

When requesting data from the database server 4, the processing circuit 15 transmits the type of data to be received and the current position information, azimuth information, vehicle identification data and the like received from the navigation device 12 to the beacon communication via the transceiver 13. Send it out to device 1.

When the beacon communication device 1 receives the data type, the current position information of the vehicle, the azimuth information and the like from the on-vehicle communication device 9, it estimates the amount of transmission data according to the data type. This estimation method may be any method, but simply, for example, how many bytes for the road map, how many bytes for the traffic information, and how many bytes for the weather forecast, may be fixed from the beginning depending on the type of information.

The beacon communication device 1 is connected to the database server 4 via the communication line 3 and
Is notified to the database server 4 of the data to be received, the current position information of the vehicle, and the like, the database server 4 returns predetermined information near the current position of the vehicle through the currently connected communication line 3.

Further, if it is predicted that all data cannot be sent to the vehicle when the vehicle leaves the communication area of the beacon communication device 1, the beacon communication device 1 determines the traveling direction of the vehicle based on the direction information. decide. Then, based on the traveling direction, a beacon that the vehicle passes next is specified, and the specified beacon (hereinafter, “next beacon”)
), Information for identifying the remaining data, and vehicle identification data are notified. The next beacon asks the database server 4 in advance to transfer this remaining data. Therefore, when the vehicle enters the communication area of the next beacon, the beacon can immediately transmit data to the vehicle-mounted communication device 9 without having to communicate with the database server, and the vehicle-mounted communication device 9 can efficiently transmit the remaining data. You can receive.

When the beacon communication device 1 predicts that there is data that has not been sent to the vehicle when the vehicle leaves the communication area of the beacon communication device 1, the beacon communication device 1 transfers the remaining data directly to the next beacon. May be. In this case,
Access to the database server 4
Concentration of load on the database server 4 can be prevented.

When the processing circuit 15 of the in-vehicle communication device 9 completes the reception of information such as road map information, traffic information, and weather forecast returned from the database server 4, the communication with the database server 4 is terminated. The content is passed to the navigation device 12. The navigation device 12 temporarily stores the given information in a predetermined memory, reads the information, and causes the display device 16 to display the read information. Also, GP
On the basis of the current position data of the vehicle given from the S receiver 11, the current position of the vehicle is also displayed so as to be superimposed on the road map.

Here, a method in which the beacon communication device 1 specifies a beacon that the vehicle will pass next will be described. Even if the direction of the road is determined, there may be a case where there is an intersection or the like and a plurality of next beacons can be selected. Even in this case, the beacon communication device 1 performs any one of “next beacon”.
Have to decide. The following method can be considered for this.

Given that the vehicle will select the road with the highest traffic volume from past statistics, the beacon installed first along that road is identified.

When the on-vehicle communication device 9 has the route data on which the vehicle is to travel, the identification data of the beacon installed along the route is sent from the on-vehicle communication device 9, and based on the identification data, To identify the next beacon. In this case, there must be a common promise for beacon identification.

When the on-vehicle communication device 9 has data on the route on which the vehicle is to travel, the beacon communication device 1 sends the route data itself and specifies the next beacon based on the route data. I do. In this case, there must be a common promise for road map information, especially link information.

It is also conceivable that the vehicle may turn at an intersection on the way before entering the communication area of the next beacon after leaving the communication area of the beacon, or may enter a parking lot. Therefore, assuming this situation, the next beacon determines the time to keep the remaining data, and if the vehicle does not enter the communication area after this time elapses, it is thought that the remaining data will be discarded. Can be This can prevent an increase in the storage capacity of the beacon.

In the description so far, the beacon communication device 1
It is assumed that the vehicle obtains traveling direction data from the on-vehicle communication device 9 in order to determine the traveling direction of the vehicle. However, it is possible to determine the traveling direction of the vehicle without acquiring the traveling direction data. For example, different markers are installed on the up lane and the down lane of the road near the location of the beacon, and the vehicle is equipped with a sensor for identifying the marker, and the identification result of this sensor is sent to the vehicle, thereby May be estimated. Also,
The identification number of the previously passed beacon may be stored in the in-vehicle communication device 9, the beacon communication device 1 may send this identification number, and the traveling direction of the vehicle may be estimated by decoding the identification number. Furthermore, in the beacon communication device 1,
By providing a Doppler radar, a camera, and the like, the traveling direction of the vehicle and the characteristics of the vehicle can be read, so that the traveling direction of the vehicle can be known.

Next, an embodiment in which the running speed of the vehicle is considered will be described.

The on-vehicle communication device 9 is the navigation device 1
If the user has 2, the traveling speed of the vehicle can be known. Therefore, when communication with the beacon communication device 1 is started, the vehicle speed information is transmitted from the in-vehicle communication device 9 to the beacon communication device 1 so that the in-vehicle communication device 9 receives the beacon, the next beacon, and the like. The amount of data that can be obtained can be estimated. This is because the limit data amount that can be transmitted by one beacon is a function of the speed of the vehicle.

As a result, when the vehicle is traveling at a very high speed, the beacon indicates that there is data that cannot be transmitted by itself, the limit data amount that can be transmitted by one beacon, the vehicle identification data, and the like. Notify beacons. The next beacon acquires, from the database server 4, the remaining data excluding the data already transferred by the beacon when the vehicle enters the communication area, from the database server 4. 9 Similarly, the next beacon is contacted.

Conversely, when the traveling speed of the vehicle is low due to traffic congestion or the like, the beacon determines that all necessary data can be transmitted by itself and does not notify the next beacon. Sometimes.

As described above, a series of data can be divided into a plurality of beacons and transmitted according to the traveling speed of the vehicle.

It should be noted that even if the on-vehicle communication device 9 does not have the navigation device 12, the beacon communication device 1 can independently know the traveling speed of the vehicle by providing a Doppler radar, a camera, and the like. In this case, there is no need to have the in-vehicle communication device 9 send the vehicle speed information to the beacon communication device 1.

In the description of the embodiment of the present invention,
Although it has been assumed that the beacon communication device is installed in each predetermined area along the road, the road-to-vehicle data communication system according to the present invention installs a base station in each predetermined area that is not necessarily along the road. Data communication may be performed between a base station and an in-vehicle communication device such as a portable information terminal or a PHS (Personal Handyphone System). Also, the case where the navigation device is included in the in-vehicle communication device has been described. However, the beacon communication device 1 is provided with a camera and the like to read the plate number of the vehicle, determine the traveling direction of the vehicle, and determine the traveling speed of the vehicle. If detected, the navigation device is not absolutely necessary.

Next, another embodiment of the present invention will be described on the assumption that the vehicle has data of a route to be traveled (claims 8 to 1).
3 related).

In the description so far, it has been assumed that it is predicted that all data cannot be sent to the vehicle when the vehicle leaves the communication area of the beacon communication device.
In this embodiment, whether all the data can be sent or not, the vehicle can efficiently acquire data related to the route to be traveled from the installed beacon communication device in the future. Form will be described.

The "data related to the route" is, for example, detailed map data of the direction to be headed, an external view or an enlarged view of an intersection that is to be turned, a photograph of the traffic congestion of the road to be headed from the sky, and the like.

In a navigation device having a function of guiding a route, if a user sets a destination, an optimum route can be calculated based on the distance or time from the current position to the destination. In some cases, the user directly sets a route to a destination.

In this case, the navigation device holds the future scheduled route as link information.

The vehicle-mounted communication device 9 transmits these pieces of link information when entering the communication area of the beacon.

These information are transferred to the database server 4 via the beacon communication device. The database server 4 determines a beacon communication device that the vehicle will pass next, and sends data related to the scheduled traveling route to the beacon communication device that the vehicle will pass next. The “related data” is, for example, data such as a detailed view of an intersection through which a vehicle passes next, traffic congestion, road information, and the like.

Therefore, the beacon communication device temporarily stores the transmitted data and, when the vehicle passes, simply transmits the data to the vehicle and immediately gives necessary data to the vehicle. be able to.

Hereinafter, a more specific description will be given with reference to FIG.

In the road map of FIG. 4, the planned traveling route of the vehicle is represented by links L1, L2, L3. N1 to N
Numeral 4 denotes a node at the start point or end point of each link. In the case of this figure, since it coincides with the position of the intersection, it is hereinafter referred to as intersections N1 to N4. It is assumed that the intersection N4 is the destination.
Beacons A, B, C, and D are installed at each intersection on the route. The lengths of the links L1, L2, and L3 are DL1, DL2, and DL3, respectively, and the link costs taking the transit time of the intersection into consideration are TL1, TL2, and TL3.

A case where a vehicle requests a detailed view of an intersection will be described as an example. When passing through the beacon A, the vehicle transmits a request for a detailed view of the intersection, identification data of the vehicle, and data of the links L1, L2, L3.

The communication device of the beacon A sends such information to a database server (not shown). The database server recognizes the position N2 of the intersection where the vehicle will pass next. The database server transmits, to the communication device of the beacon B, the identification data of the vehicle and the data of the detailed view of the previous intersection N3 before the passing time.
After confirming that the vehicle is the vehicle, the communication device of the beacon B transmits the data to the vehicle.

Therefore, when the vehicle approaches the intersection N2, the vehicle immediately communicates with the communication device of the beacon B and can know the shape of the intersection N3, so that the vehicle can definitely pass through the intersection N3. It is also possible to know the state of the facilities near the intersection N3.

When passing the beacon B, a detailed view of the intersection can be requested again. In this case, when the vehicle approaches the intersection N3, the vehicle immediately communicates with the communication device of the beacon C, and the intersection N4 You can know the shape and the like.

In the above example, a beacon is installed at each intersection, but a beacon may not be installed at a certain passing intersection. In this case, it is not possible to obtain the data of the detailed view of the next intersection after the passing intersection. Therefore, it is preferable to transmit the data of the detailed view of the two intersections from the beacon of the preceding passing intersection.

The following is a description of the example shown in FIG.
If the beacon C is not installed at the intersection N3, the database server can determine that there is an intersection where the beacon is not installed on the scheduled traveling route.
The detailed data of the intersection N4 is transmitted together with the detailed data of 3. Therefore, even if there is an intersection where no beacon is installed, the vehicle can obtain detailed data of the next intersection without any problem.

In the above embodiment, the database server transmits data related to the scheduled travel route of the vehicle to the beacon communication device, and the beacon communication device stores the transmitted data, Data was transmitted when the vehicle passed. However, this requires a storage device for storing data for the number of passing vehicles on the beacon side.

Therefore, when the in-vehicle communication device enters the communication area of the beacon, the link information and the information on the passage time of the link (link cost information) may be transmitted, or the database server may determine in advance the link of the jurisdiction area. As holding the link cost data, the database server determines the estimated time of vehicle passage based on the calculation (at this time,
If there is a change in link cost due to an accident, traffic congestion, etc., it is a matter of course that the change is added).
It is conceivable that the data is sent to the beacon communication device, and the beacon communication device temporarily stores the data and transmits the data to the vehicle, and when the vehicle has passed, the stored data is promptly deleted.

In this case, the beacon communication device stores the data related to the scheduled travel route immediately before the scheduled vehicle passing time, but deletes the stored data when the passing of the vehicle is completed. The memory time per hit is
It takes only a very short time. Therefore, the rotation of the storage area is improved, and the storage capacity can be saved. In the method described so far, data is transferred in advance from the database server to the beacon communication device, stored in the storage device of the beacon communication device, and when the vehicle enters the communication area of the beacon, the data is transmitted from the beacon. It provided data to the vehicle. However, if the beacon has no storage device, such a method cannot be used.

Therefore, when the in-vehicle communication device enters the communication area of the beacon, the link information and the link cost information are transmitted, or the link cost data of the link in the jurisdiction is held in advance by the database server. The database server determines the estimated passing time of the vehicle based on the calculation, and sends data related to the planned traveling route to the beacon communication device in accordance with the estimated passing time, and the beacon communication device specifies the vehicle. It is conceivable that the data is transmitted to the vehicle as it is.

In this case, it is necessary to reserve a communication band (for example, a time slot) of the beacon communication device at the time so that the data can be transmitted to the vehicle as it is at the scheduled passage time. By making this reservation, when the vehicle passes through the communication area of the beacon, even if another vehicle that has not reserved a communication band requests data, transmission to the vehicle is prioritized. Therefore, data can be reliably transferred to this vehicle.

When transmitting data based on the reservation of the communication band, the same data is requested from a plurality of vehicles.
If there is an overlap in the time when the beacon passes through the communication area, data can be provided (multicasted) to a plurality of vehicles by one transmission by overlappingly reserving the same communication band.

As a result, apparently, the information transfer efficiency is multiplied. This can be done because the database server predicts the passing time in advance based on information from a plurality of vehicles.

[0084]

As described above, according to the ground communication apparatus used in the road-to-vehicle data communication system of the present invention, if it is determined that data cannot be transmitted to the on-vehicle communication apparatus at one time, the vehicle will continue to run. Anticipate other terrestrial communication devices on the road that will run, and in cooperation with this "other terrestrial communication device", the data can be divided and transmitted, so a large amount of data can be efficiently transmitted to the on-vehicle communication device. Can be sent.

In particular, according to the invention as set forth in claim 8 or claim 9, since the scheduled travel route of the vehicle can be specifically known, the other ground communication device which the vehicle is expected to pass next can be Necessary data can be transferred. Also,
The vehicle only needs to communicate with the ground communication device, and does not require a line for directly connecting the vehicle and the information holding device, so that the equipment burden on the vehicle is reduced.

According to the tenth aspect of the present invention, the time for retaining data in the storage means of the terrestrial communication apparatus can be minimized, and the storage capacity can be minimized.

According to the eleventh aspect of the present invention, since the communication band at the time when the vehicle enters the communication area of the ground communication device can be reserved, if the untransmitted data transfer means transfers the data at the predicted time, The data can be transmitted to the vehicle as it is. Therefore, it is not necessary to provide data storage means in the ground communication device, and the configuration of the ground communication device can be simplified.

According to the twelfth aspect of the present invention, data can be transmitted from the ground communication apparatus to a plurality of vehicles at once, so that data transmission efficiency can be improved.

According to the thirteenth aspect, the on-vehicle communication device does not request the related data along the route to the destination at one time, but requests the related data in the form of a fragment for each installation section of the terrestrial communication device. Therefore, the amount of data transmission per operation can be reduced. Therefore, there is a high possibility that required data can be transmitted at one time, and there is no remaining data.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a road-vehicle data communication system for providing road map information, traffic information, and the like to a vehicle-mounted communication device mounted on a vehicle.

FIG. 2 is a block diagram illustrating an electrical configuration of the beacon communication device.

FIG. 3 is a block diagram illustrating an electrical configuration of a vehicle-mounted communication device mounted on a vehicle for transmitting and receiving various data to and from a beacon communication device.

FIG. 4 is a map of a road where a beacon is installed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Beacon communication device 3 Communication line 4 Database server 5 Transceiver 6 Processing circuit 7 Transmission terminal 9 In-vehicle communication device 10 GPS antenna 11 GPS receiver 12 Navigation device 13 Transceiver 14 Road map database 15 Processing circuit 16 Display device

Claims (13)

[Claims] 1. A route for arranging a plurality of terrestrial communication devices, a terrestrial communication device having received a data transmission request from the on-vehicle communication device accesses a database, acquires necessary data, and provides the data to the on-vehicle communication device. Used in an inter-vehicle data communication system, a traveling direction obtaining means for knowing the traveling direction of the vehicle, a data amount estimating means for estimating a series of data amounts to be transmitted to the vehicle-mounted communication device, and determining that all data cannot be transmitted to the vehicle-mounted communication device. If not, based on the traveling direction of the vehicle, having untransmitted data notifying means for notifying other terrestrial communication devices that the vehicle is expected to pass next, information that specifies untransmitted data A ground communication device characterized by the above-mentioned. 2. An on-vehicle communication device used in correspondence with the terrestrial communication device according to claim 1, wherein a traveling direction of the own vehicle is known, and data of the traveling direction is transmitted to the terrestrial communication device. An in-vehicle communication device comprising a means. 3. A route in which a plurality of terrestrial communication devices are arranged, and a terrestrial communication device that has received a data transmission request from an on-vehicle communication device accesses a database to obtain necessary data and provides the data to the on-vehicle communication device. Used in an inter-vehicle data communication system, a traveling direction obtaining means for knowing the traveling direction of the vehicle, a traveling speed acquiring means for knowing the traveling speed of the vehicle, and a data amount estimating means for estimating a series of data amounts to be transmitted to the on-vehicle communication device. If it is determined that all data cannot be transmitted to the in-vehicle communication device at the traveling speed of the vehicle acquired by the traveling speed acquisition unit, the vehicle is expected to pass next based on the traveling direction of the vehicle. And a not-yet-transmitted data notifying means for notifying the information identifying the untransmitted data to the above-mentioned terrestrial communication device. 4. An on-vehicle communication device used in correspondence with the terrestrial communication device according to claim 3, wherein the traveling direction of the own vehicle is known, and the traveling direction data is transmitted to the terrestrial communication device. A vehicle-mounted communication device, comprising: means for traveling the vehicle, and a traveling speed transmitting unit for knowing the traveling speed of the vehicle and transmitting data on the traveling speed to the ground communication device. 5. A route in which a plurality of terrestrial communication devices are arranged, and a terrestrial communication device that has received a data transmission request from an on-vehicle communication device accesses a database to acquire necessary data and provides the data to the on-vehicle communication device. It is used in an inter-vehicle data communication system, and a traveling route acquisition unit that knows a traveling route of a vehicle, a data amount estimating unit that estimates a series of data amounts to be transmitted to the vehicle-mounted communication device, and cannot transmit all data to the vehicle-mounted communication device When it is determined, based on the travel route of the vehicle, untransmitted data notifying means for notifying other ground communication devices that the vehicle is expected to pass next to information identifying untransmitted data, A terrestrial communication device comprising: 6. An in-vehicle communication device used in correspondence with the ground communication device according to claim 5, further comprising a scheduled travel route transmitting means for transmitting data of a scheduled travel route of the own vehicle to the ground communication device. An in-vehicle communication device characterized by the above-mentioned. 7. A terrestrial communication device together with or in place of the untransmitted data notifying means,
6. The terrestrial communication apparatus according to claim 1, further comprising untransmitted data transfer means for transferring untransmitted data itself. 8. At least one information holding device is installed, a plurality of terrestrial communication devices connected to the information holding device via a communication line are arranged, and the terrestrial communication device receiving a data transmission request from the on-vehicle communication device holds the information. A road-to-vehicle data communication system that accesses a database of a device to obtain necessary data and provides the data to the on-vehicle communication device, wherein the ground communication device includes a planned traveling route acquisition unit that knows a planned traveling route of the vehicle. And a scheduled travel route notifying means for notifying the information holding device of a scheduled travel route of the vehicle, wherein the information holding device is scheduled to pass the vehicle next based on the notified scheduled travel route. A road-to-vehicle data communication system comprising a data transfer means for transferring data to another ground communication device. 9. An on-vehicle communication device used in correspondence with the ground communication device according to claim 8, comprising a traveling route transmitting means for transmitting data of the traveling route of the own vehicle to the ground communication device. An in-vehicle communication device characterized by the above-mentioned. 10. An information holding apparatus comprising: a time predicting means for predicting a time at which a vehicle will enter a communication area of another terrestrial communication apparatus which is expected to pass next;
The data is transferred to the other terrestrial communication device at a timing immediately before the predicted time. The terrestrial communication device has storage means for temporarily storing the transferred data, and is used when the vehicle leaves the communication area. 9. The road-to-vehicle data communication system according to claim 8, wherein said storage in said storage means is deleted. 11. An information holding device comprising: a time predicting means for predicting a time at which a vehicle will enter a communication area of another terrestrial communication device scheduled to pass next; Communication band reserving means for reserving a communication band at the time of entering the communication area, wherein the untransmitted data transfer means transfers data to the other terrestrial communication device at the predicted time. Item 9. A road-to-vehicle data communication system according to item 8. 12. A communication band reserving means for reserving the same communication band when a plurality of vehicles receiving the same data transmission request stay in the communication area of the same ground communication device at the same time. The road-to-vehicle data communication system according to claim 11, wherein: 13. A vehicle-mounted communication device according to claim 1, wherein the vehicle-mounted communication device transmits a route from another ground communication device to which the vehicle is expected to pass to another ground communication device to be passed next. 9. The road-to-vehicle data communication system according to claim 8, wherein a request for transmission of data related to the request is made.