JP2010204949A - Data transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive data transmission system for efficiently transmitting a large quantity of data to a moving vehicle. <P>SOLUTION: The data transmission system includes: a center 300 for storing data; roadside devices 400, 410, 420 installed on a roadside; and a vehicle 200 for transmitting vehicle information to the center and communicating with the roadside devices. The center predicts the traveling path of the vehicle on the basis of the vehicle information received from the vehicle, and transmits the data held by itself to the roadside devices installed in the predicted path to make the same be held. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a data transmission system for transmitting a large amount of data to a vehicle, and more particularly to a technique for efficiently performing data transmission.

  In recent years, devices for recording television broadcasts such as HDD (Hard Disk Drive) recorders for a long time, or multimedia data such as video and audio, not limited to recording television broadcasts, are generally stored. Equipment for this purpose has become widespread. In many cases, HDDs are used as storage media for these devices. However, the size of files storing multimedia data stored in HDDs as HDDs are reduced in price and capacity are increased. It's getting bigger.

  Many of these devices can be connected to a network, and multimedia data stored in a home server connected to a home network can be transmitted to other devices and played back. ing.

  Under such circumstances, there is an increasing demand for reproducing and browsing multimedia data not only in the home but also in the vehicle. By the way, since the vehicle moves, in order to reproduce and browse the multimedia data in the vehicle, it is necessary to transmit the multimedia data to the vehicle by wireless communication. Mobile phones that are most popular as the infrastructure for wireless communication at the present time have a wide communication range, but the data transmission speed of the line is slow. This requires a long time.

  Moreover, as an infrastructure that enables high-speed wireless communication, there is dedicated short-range communication represented by DSRC (Dedicated Short Range Communication) capable of performing wireless communication at a speed of several Mbps. Is in the range of several meters to several hundred meters and is narrow. For this reason, even if it tries to transmit the multimedia data mentioned above to the vehicle, the communication area is narrow and the vehicle moves, so the vehicle goes out of the communication area during data transmission, and all the multimedia data is transmitted. There is a problem that it may not be possible.

  As a method for solving such a problem, an area in which data to be transmitted to a vehicle is divided and temporarily stored in each of a plurality of roadside devices installed beside the road so that the vehicle can communicate with the roadside device. When the vehicle enters, the roadside device transmits the temporarily stored divided data to the vehicle, and repeats this transmission every time the vehicle passes the roadside device, thereby transferring large file size data to the vehicle. There is a technology to transmit.

  For example, Patent Document 1 discloses a wireless communication system that is effective for solving a network traffic problem on the premise of spot access. In this wireless communication system, the interval between the detection station and the local base station is determined by the interval between the local base station and the in-vehicle terminal while the in-vehicle terminal is detected by the detection station and reaches the communication area of the local base station. It is set to be able to transmit information to. Each local base station detects the terminal station ID of the in-vehicle terminal as a first trigger before a predetermined distance from the communication area, and also detects that the in-vehicle terminal has arrived at the communication area at the boundary of the communication area. Detect as a trigger. The detection position intervals of both triggers are close to each other so that even if there are a plurality of in-vehicle terminals, the order of the in-vehicle terminals to be detected does not change. Therefore, after preparing to transmit the information supplied by the first trigger, it is only necessary to transmit the information in units by the second trigger.

JP 2003-229801 A

  However, the above-described conventional technology is assumed to be applied when the roadside machine is arranged in an environment where the road is not branched, such as an expressway, and is in a straight line. In an environment where there is a possibility that the vehicle may travel along various routes, there is a problem that it is not known to which roadside device data should be transmitted in advance.

  In addition, even if it is recognized that a vehicle has entered the roadside machine communication area and data to be transmitted to the vehicle is acquired from the outside, the roadside machine communication area is so narrow that the vehicle can be communicated in a short time. There is a problem that data cannot be transmitted because it goes out. Furthermore, it is disadvantageous in terms of cost to have all the roadside machines hold all data in advance.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an inexpensive data transmission system capable of efficiently transmitting a large amount of data to a moving vehicle.

  In order to solve the above-described problems, the present invention includes a center that holds data, a roadside device installed beside a road, and a vehicle that transmits vehicle information to the center and communicates with the roadside device. The center is configured to predict a route on which the vehicle travels based on vehicle information received from the vehicle, and transmit and hold the data held by the roadside device installed on the predicted route. Has been.

  According to the present invention, the route on which the vehicle travels is predicted in advance, and the roadside device existing on the predicted route is configured to transmit and hold the data to be transmitted to the vehicle. If data configured to be received in sequence is received sequentially, large file size data can be efficiently transmitted to the vehicle.

It is a figure which shows the structure of the data transmission system which concerns on Embodiment 1 of this invention. It is a block diagram which shows the detailed structure of the center used with the data transmission system which concerns on Embodiment 1 of this invention. It is a block diagram which shows the detailed structure of the roadside machine used with the data transmission system which concerns on Embodiment 1 of this invention. It is a block diagram which shows the detailed structure of the vehicle used with the data transmission system which concerns on Embodiment 1 of this invention. It is a figure which shows the arrangement | positioning of the vehicle and roadside machine assumed in the data transmission system which concerns on Embodiment 1 of this invention, and the detail of a roadside machine periphery. It is a sequence chart which shows the outline of the process performed with the data transmission system which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the data transmission system which concerns on Embodiment 2 of this invention. It is a block diagram which shows the detailed structure of the center used with the data transmission system which concerns on Embodiment 2 of this invention. It is a sequence chart which shows the outline of the process performed with the data transmission system which concerns on Embodiment 2 of this invention. It is a figure which shows the structure of the data transmission system which concerns on Embodiment 3 of this invention. It is a block diagram which shows the detailed structure of the center used with the data transmission system which concerns on Embodiment 3 of this invention. It is a sequence chart which shows the outline of the process performed with the data transmission system which concerns on Embodiment 3 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
The data transmission system according to the first embodiment of the present invention uses the vehicle information obtained from the vehicle to predict a route on which the vehicle will travel, and for roadside devices that exist on the predicted route, All data of a large file size to be transmitted to the vehicle is transmitted in advance, and the vehicle sequentially acquires data from the roadside device each time it passes by the roadside device, so that the final large file size is obtained. The data can be obtained.

  FIG. 1 is a diagram illustrating a configuration of a data transmission system according to the first embodiment. This data transmission system includes a home server 100, a vehicle 200, a center 300, roadside devices 400, 410 and 420, networks 500, 510 and 520, and communication paths 501, 502, 511, 512, 521, 522, 523, and 524. 525, 526 and 527. In this data transmission system, the number of roadside units is set to “3” for the sake of simplicity, but the number of roadside units can be arbitrarily determined. The same applies to the number of networks and communication paths.

  Home server 100 stores data to be transmitted to vehicle 200. The vehicle 200 transmits a data request for requesting acquisition of data stored in the home server 100 to the center 300 via the communication path 512, the network 510, and the communication path 511. In addition, the vehicle 200 sequentially transmits its own vehicle information to the center 300 via the communication path 512, the network 510, and the communication path 511. Details of the vehicle 200 will be described later.

  In response to the data request from the vehicle 200, the center 300 acquires data from the home server 100 via the communication path 502, the network 500, and the communication path 501. Further, the center 300 predicts a route on which the vehicle 200 will travel based on the vehicle information received from the vehicle 200, and the home server 100 with respect to the roadside devices 400, 410, and 420 existing on the predicted route. Is acquired via the communication path 521, the network 520, and the communication paths 522, 523, or 524, respectively. Details of the center 300 will be described later.

  Roadside machines 400, 410 and 420 are installed beside the road. Each of these roadside devices 400, 410 and 420 holds data received from the center 300, and when the vehicle 200 enters its own communication area, the communication routes 525, 526 or 527 to the vehicle 200. Send data via Details of these roadside machines 400, 410 and 420 will be described later.

  Next, details of the center 300 will be described. FIG. 2 is a block diagram showing a detailed configuration of the center 300. The center 300 includes network interfaces 301, 302, and 303, a prediction unit 304, a storage unit 305, and a control unit 306. The network interface 301 is connected to the network 500 via the communication path 501. The network interface 302 is connected to the network 510 via the communication path 511. The network interface 303 is connected to the network 520 via the communication path 521.

  The prediction unit 304 acquires vehicle information sent from the vehicle 200 via the network interface 302, and predicts a route on which the vehicle 200 will travel based on the acquired vehicle information. The storage unit 305 holds data acquired from the home server 100 via the network interface 301. The control unit 306 determines a roadside device to which data is to be transmitted based on the prediction result of the prediction unit 304, and sends the data stored in the storage unit 305 to the determined roadside device via the network interface 303. Control to transmit.

  Next, details of the roadside devices 400, 410, and 420 will be described. In addition, since each structure of the roadside machines 400, 410, and 420 is the same, only the roadside machine 400 is demonstrated below. FIG. 3 is a block diagram showing a detailed configuration of the roadside machine 400. The roadside machine 400 includes network interfaces 401 and 402, a vehicle priority determination unit 403, a storage unit 404, and a control unit 405.

  The network interface 401 is connected to the network 520 via the communication path 522. Network interface 402 is connected to vehicle 200 via communication path 525. The connection between the roadside machine 400 and the vehicle 200 is established only when the vehicle 200 is within the communication area of the roadside machine 400.

  The vehicle priority determination unit 403 preferentially communicates with which vehicle when a plurality of vehicles are within the communication area of the roadside device 400 according to information obtained from the vehicle 200 via the network interface 402. Determine what should be done. This determination is made based on how far out of all data to be transmitted to the vehicle is completed, that is, based on the ratio of the data amount already received by the vehicle 200 to the total data amount. For example, when comparing a vehicle that has received all data in the remaining one transmission and a vehicle that has received only about half of all data, the former priority is determined to be high. In addition, when the data received by the vehicle 200 is sequentially read, the priority may be determined depending on how far the reading position is from the final position of the data received by the vehicle 200. it can.

  The storage unit 404 holds data received from the center 300 via the network interface 401. The control unit 405 acquires transmission position information (information indicating a data position at which transmission is completed) from the vehicle 200 via the network interface 402, and from which data to start transmission based on the acquired transmission position information. In other words, the start position is determined, and the data stored in the storage unit 404 is sequentially read from the start position and transmitted to the vehicle 200 via the network interface 402. As described above, this data transmission is performed only while the communication path 525 is established. For this reason, for example, when the vehicle 200 is stopped in the communication area of the roadside unit, data transmission is continuously performed while the vehicle 200 is stopped.

  In addition, the control unit 405 erases the data held in the storage unit 404 and not transmitted to the vehicle 200 within a certain time in order to effectively use the limited resources of the roadside device 400. The center 300 is notified of this. When the center 300 receives the notification that the data has been deleted, the center 300 recognizes that the route prediction has failed, and performs control so that a series of operations is performed again from the prediction of the vehicle route.

  Next, details of the vehicle 200 will be described. FIG. 4 is a block diagram showing a detailed configuration of the vehicle 200. The vehicle 200 includes a network interface 201 and 202, a navigation system 203, a vehicle information management unit 204, a travel history management unit 205, a direction indicator 206, a vehicle speed sensor 207, a GPS (Global Positioning System) 208, a coupling unit 209, and a storage unit 210. In addition, a control unit 211 is provided.

  The network interface 201 is connected to the network 510 via the communication path 512. The network interface 202 is connected to the roadside devices 400, 410, and 420 via communication paths 525, 526, and 527, respectively. These connections are established only when the vehicle 200 is within the communication area of the roadside machine 400, 410 or 420.

  When the navigation system 203 is navigating the driving route to the driver, the navigation system 203 sends route information representing the guidance route presented to the driver to the vehicle information management unit 204. The travel history management unit 205 manages the past travel history of the vehicle 200. The travel history information managed by the travel history management unit 205 is sent to the vehicle information management unit 204 as history information.

  The direction indicator 206 sends state information representing the content of the instruction to the vehicle information management unit 204 when an operation for instructing the direction is performed by the driver. The vehicle speed sensor 207 detects the current traveling speed of the vehicle and sends it to the vehicle information management unit 204 as traveling speed information. The GPS 208 calculates the current position (latitude and longitude) and traveling direction of the vehicle 200, and sends the current position information and traveling direction information to the vehicle information management unit 204.

  The vehicle information management unit 204 includes route information from the navigation system 203, travel history information from the travel history management unit 205, state information from the direction indicator 206, travel speed information from the vehicle speed sensor 207, and current information from the GPS 208. The position information and the traveling direction information are managed and transmitted as vehicle information to the center 300 via the network interface 201. The transmission of the vehicle information is sequentially performed when a certain time interval or vehicle information changes.

  In response to an instruction from the user, the control unit 211 requests the center 300 to acquire data stored in the home server 100 via the network interface 201. When the vehicle 200 travels on the road and a communication path with the roadside machine is established via the network interface 202, the control unit 211 transmits a data request to the roadside machine. In addition, data sent from the roadside machine in response to this data request is received and stored in the storage unit 210.

  In addition, when the vehicle 200 has already received a part of data from another roadside machine, when transmitting a data request, the data already stored in the storage unit 210 is confirmed, and from the continuation of the data Transmission position information for reception is added. When recognizing that all data has been received, the control unit 211 instructs the combining unit 209 to combine the data stored in the storage unit 210. In response to this instruction, the combining unit 209 combines the data stored in the storage unit 210.

  Next, the operation of the data transmission system according to the first embodiment configured as described above will be described. FIG. 5 is a diagram illustrating the arrangement of vehicles and roadside units assumed in the data transmission system according to Embodiment 1, and details of the vicinity of the roadside units. Taking the roadside machine 400 as an example, an antenna 441 is connected to the roadside machine 400, and there is a communication area 442 through which the antenna 441 can communicate. The communication area 442 is an area having a diameter of about several meters to several hundred meters, and a plurality of roadside devices are installed so that the communication areas do not overlap each other. FIG. 5 shows a state in which the vehicle 200 is traveling toward the roadside machine 400, and in this state, the center 300 predicts a route on which the vehicle 200 will travel. In the following description, it is assumed that the center 300 is predicted to travel on a road where the roadside devices 410 and 420 exist.

  FIG. 6 is a sequence chart illustrating an outline of processing performed in the data transmission system according to the first embodiment. First, the vehicle 200 transmits a data request for requesting acquisition of data desired to be transmitted from the home server 100 to the center 300 (600). In response to the data request from the vehicle 200, the center 300 transmits the data request to the home server 100 (601). In response to the data request from the center 300, the home server 100 transmits all data to the center 300 (602).

  On the other hand, the vehicle 200 sequentially transmits vehicle information to the center 300 (603). Based on the vehicle information received from the vehicle 200, the center 300 predicts a route on which the vehicle 200 will travel thereafter (604). Then, using the predicted route and the position information of the roadside devices 400, 410, and 420 that the center 300 holds in advance, the roadside device that the vehicle 200 may pass by, that is, the roadside on which data is to be transmitted. The machine is determined (605). Here, it is assumed that the roadside devices 400, 410, and 420 are determined as data transmission destinations.

  The center 300 transmits all data to the roadside machine 400 (606). The center 300 transmits all data to the roadside device 410 (607). Further, the center 300 transmits all data to the roadside machine 420 (608). Thereafter, when the vehicle 200 enters the communication area of the roadside device 400, the vehicle 200 transmits a data transmission request to the roadside device 400 (609). The roadside device 400 transmits data to the vehicle 200 in response to the data transmission request (610). When the data transmission is completed, the roadside machine 400 transmits a data transmission notification to the center 300 (611). As described above, since the communication area is limited, all data may not be transmitted if the size of the data to be transmitted is large. In this case, the vehicle 200 holds transmission position information indicating how much of all data has been received.

  Next, when the vehicle 200 enters the communication area of the roadside device 410, the vehicle 200 transmits a data transmission request to the roadside device 410 (612). This data transmission request includes the transmission position information described above. In response to the data transmission request, the roadside device 410 starts transmission from the data that has not yet been received by the vehicle 200 indicated by the transmission position information among all the data (613). When the transmission is completed, the roadside device 410 transmits a data transmission notification to the center 300 (614).

  Next, when the vehicle 200 enters the communication area of the roadside device 420, the vehicle 200 transmits a data transmission request to the roadside device 420 (615). This data transmission request includes the transmission position information described above. In response to the data transmission request, the roadside machine 420 starts transmission from data that has not yet been received by the vehicle 200 indicated by the transmission position information among all the data (616). When the transmission is completed, the roadside device 410 transmits a data transmission notification to the center 300 (617). In this example, transmission of all data to the vehicle 200 is completed at this point. The vehicle 200 combines the obtained data (618). Thereby, the original data is obtained.

  Thereafter, the vehicle 200 notifies the center 300 that the reception of all data has been completed (619). In response to the notification from the vehicle 200, the center 300 notifies the home server 100 that the transmission of all data is completed, and completes a series of data transmission (620).

  As described above, according to the data transmission system according to the first embodiment of the present invention, when data with a large file size is transmitted to a vehicle, the route on which the vehicle travels is predicted in advance and exists on the predicted route. Since the data to be transmitted is transmitted to the roadside machine, the data transmission can be performed efficiently and reliably.

Embodiment 2. FIG.
In the data transmission system according to the second embodiment of the present invention, the vehicle information obtained from the vehicle is used to predict the route on which the vehicle will travel, and for the roadside units existing on the predicted route, The data of a large file size to be transmitted to the vehicle is divided and transmitted in advance, and the vehicle finally obtains the divided data from the roadside device every time it passes by the roadside device. In this way, data with a large file size can be obtained.

  FIG. 7 is a diagram illustrating a configuration of the data transmission system according to the second embodiment. This data transmission system is the same as the configuration of the data transmission system according to the first embodiment shown in FIG. 1 except that the center 300 of the data transmission system according to the first embodiment is changed to the center 310. It is. In the following, the same components as those of the data transmission system according to the first embodiment are denoted by the same reference numerals as those used in the description of the first embodiment, and the description thereof will be omitted. To do.

  In response to the data request from the vehicle 200, the center 310 acquires data from the home server 100 via the communication path 502, the network 500, and the communication path 501. Further, the center 310 predicts a route on which the vehicle 200 will travel based on the vehicle information received from the vehicle 200, and communicates the communication route 521 to the roadside devices 400, 410, and 420 existing on the predicted route. The data to be transmitted is divided and transmitted via the network 520 and the communication paths 522, 523, or 524, respectively. The roadside devices 400, 410, and 420 hold data obtained from the center 310, and transmit data divided to the vehicle 200 when the vehicle 200 travels within its own communication area.

  FIG. 8 is a block diagram showing a detailed configuration of the center 310. The center 310 includes network interfaces 311, 312 and 313, a prediction unit 314, a division unit 315, a storage unit 316 and a control unit 317. The network interface 311 is connected to the network 500 via the communication path 501. The network interface 312 is connected to the network 510 via the communication path 511. The network interface 313 is connected to the network 520 via the communication path 521.

  The prediction unit 314 acquires vehicle information sent from the vehicle 200 via the network interface 312 and predicts a route on which the vehicle 200 will travel based on the acquired vehicle information. The storage unit 316 holds data acquired from the home server 100 via the network interface 311.

  The dividing unit 315 divides the data held in the storage unit 316 into data to be transmitted to each roadside device based on the prediction result by the prediction unit 314. Each of the data divided by the dividing unit 315 is referred to as “divided data”. The size of the divided data is determined to be a value smaller than the maximum size of data that can be transmitted when the vehicle 200 travels within the communication area of the roadside machine in each roadside machine. It should be noted that at the time of this division, for security reasons, it may be configured to perform processing such as encryption that cannot be restored to the original data unless all of the divided data is prepared.

  The control unit 317 determines a roadside device to which data is to be transmitted based on the prediction result of the prediction unit 314, and sends the divided data stored in the storage unit 316 to the determined roadside device via the network interface 313. Control to transmit.

  Next, the operation of the data transmission system according to the second embodiment configured as described above will be described. The arrangement of vehicles and roadside units assumed in the data transmission system according to the second embodiment and the details of the vicinity of the roadside units are the same as those in the first embodiment shown in FIG. That is, as shown in FIG. 5, in a state where the vehicle 200 is traveling toward the roadside machine 400, the center 310 predicts a route on which the vehicle 200 will travel. In the following description, it is assumed that the center 310 is predicted to travel on a road where the roadside devices 410 and 420 exist.

  FIG. 9 is a sequence chart illustrating an outline of processing performed in the data transmission system according to the second embodiment. First, the vehicle 200 transmits a data request for requesting acquisition of data desired to be transmitted from the home server 100 to the center 310 (700). In response to the data request from the vehicle 200, the center 310 transmits the data request to the home server 100 (701). In response to the data request from the center 310, the home server 100 transmits all data to the center 310 (702).

  On the other hand, the vehicle 200 sequentially transmits vehicle information to the center 310 (703). Based on the vehicle information received from the vehicle 200, the center 310 predicts a route that the vehicle 200 will travel on thereafter (704). Then, using the predicted route and the position information of the roadside devices 400, 410 and 420 previously held by the center 310, the roadside device on which the vehicle 200 may pass by, that is, the roadside on which the data is to be transmitted. The machine is determined (705). Here, it is assumed that roadside devices 400, 410, and 420 are determined as data transmission destinations.

  Next, the center 310 divides the data in order to transmit the data to the roadside devices 400, 410, and 420 determined as the data transmission destination (706). Thereafter, the center 310 transmits the divided data to the roadside device 400 (707). Further, the center 310 transmits the divided data to the roadside device 410 (708). Further, the center 310 transmits the divided data to the roadside device 420 (709). Thereafter, when the vehicle 200 enters the communication area of the roadside device 400, the vehicle 200 transmits a data transmission request to the roadside device 400 (710). The roadside device 400 transmits the divided data to the vehicle 200 in response to the data transmission request (711). When the transmission of the divided data is completed, the roadside machine 400 transmits a data transmission notification to the center 310 (712).

  Next, when the vehicle 200 enters the communication area of the roadside device 410, the vehicle 200 transmits a data transmission request to the roadside device 410 (713). The roadside machine 410 transmits the divided data to the vehicle 200 in response to the data transmission request (714). When the transmission is completed, the roadside device 410 transmits a data transmission notification to the center 310 (715).

  Next, when the vehicle 200 enters the communication area of the roadside unit 420, the vehicle 200 transmits a data transmission request to the roadside unit 420 (716). The roadside device 420 transmits the divided data to the vehicle 200 in response to the data transmission request (717). When the transmission is completed, the roadside device 420 transmits a data transmission notification to the center 310 (718). In this example, transmission of all data to the vehicle 200 is completed at this point. The vehicle 200 combines the obtained data (719). Thereby, the original data is obtained.

  Thereafter, the vehicle 200 notifies the center 310 that the reception of all data has been completed (720). In response to the notification from the vehicle 200, the center 310 notifies the home server 100 that the transmission of all data has been completed, and completes a series of data transmission (721).

  As described above, according to the data transmission system according to the second embodiment of the present invention, when data with a large file size is transmitted to a vehicle, the route on which the vehicle travels is predicted in advance and exists on the predicted route. Since the divided data obtained by dividing the data to be transmitted is transmitted to the roadside machine to be transmitted, the amount of data to be held by the roadside machine can be reduced, and data transmission is performed efficiently and reliably be able to.

Embodiment 3 FIG.
In the data transmission system according to the third embodiment of the present invention, the vehicle information obtained from the vehicle is used to predict the route on which the vehicle will travel, and for the roadside units existing on the predicted route, Divide large file size data to be transmitted to the vehicle and transmit the data with the bit rate appropriately selected in advance, and the vehicle is divided from the roadside device every time it passes by the roadside device. By sequentially acquiring the data, it is possible to reproduce the data without interruption so that the data of the largest file size is finally at hand.

  FIG. 10 is a diagram illustrating a configuration of a data transmission system according to the third embodiment. This data transmission system is the same as the configuration of the data transmission system according to the second embodiment shown in FIG. 7 except that the center 310 of the data transmission system according to the second embodiment is changed to the center 320. It is. In the following, the same components as those of the data transmission system according to the second embodiment are denoted by the same reference numerals as those used in the description of the second embodiment, and the description thereof is omitted. To do.

  In response to the data request from the vehicle 200, the center 320 acquires data from the home server 100 via the communication path 502, the network 500, and the communication path 501. Further, the center 320 predicts a route on which the vehicle 200 will travel based on the vehicle information received from the vehicle 200, and communicates the communication route 521 to the roadside devices 400, 410, and 420 existing on the predicted route. The data to be transmitted is divided and transmitted via the network 520 and the communication paths 522, 523, or 524, respectively.

  Further, the center 320 estimates from the vehicle information received from the vehicle 200 the reproduction completion time of the data currently being reproduced by the vehicle, and the reproduction is predicted to be completed before the data is received from the roadside device. When the data is divided, the data subjected to processing for extending the reproduction time per size is transmitted to the roadside devices 400, 410 and 420. The roadside devices 400, 410, and 420 hold the data obtained from the center 320 and transmit the data divided to the vehicle 200 when the vehicle 200 travels within its own communication area.

  FIG. 11 is a block diagram showing a detailed configuration of the center 320. The center 320 includes network interfaces 321, 322, and 323, a prediction unit 324, a division processing unit 325, a storage unit 326, and a control unit 327. The network interface 321 is connected to the network 500 via the communication path 501. The network interface 322 is connected to the network 510 via the communication path 511. The network interface 323 is connected to the network 520 via the communication path 521.

  The prediction unit 324 acquires vehicle information sent from the vehicle 200 via the network interface 322, and predicts a route on which the vehicle 200 will travel based on the acquired vehicle information. The storage unit 326 holds data acquired from the home server 100 via the network interface 321.

  Based on the prediction result by the prediction unit 324, the division processing unit 325 divides the data held in the storage unit 326 into divided data to be transmitted to each roadside device and processes the data. The size of the divided data is determined to be a value smaller than the maximum size of data that can be transmitted when the vehicle 200 travels within the communication area of the roadside machine in each roadside machine. It should be noted that at the time of this division, for security reasons, it may be configured to perform processing such as encryption that cannot be restored to the original data unless all of the divided data is prepared.

  The division processing unit 325 is low when processing the divided data, for example, by transcoding to lower the bit rate or when the data corresponds to a plurality of bit rates such as hierarchical encoding. Processing such as extracting bit rate data is performed.

  The control unit 327 determines a roadside device to which data is to be transmitted based on the prediction result of the prediction unit 324, and transmits the divided data stored in the storage unit 326 to the determined roadside device via the network interface 323. And control to transmit.

  Next, the operation of the data transmission system according to the third embodiment configured as described above will be described. The arrangement of vehicles and roadside units assumed in the data transmission system according to the third embodiment and the details of the vicinity of the roadside units are the same as those in the first embodiment shown in FIG. That is, as shown in FIG. 5, in a state where the vehicle 200 is traveling toward the roadside machine 400, the center 320 predicts a route on which the vehicle 200 will travel. In the following description, it is assumed that the center 320 is predicted to travel on a road where the roadside devices 410 and 420 exist.

  FIG. 12 is a sequence chart illustrating an outline of processing performed in the data transmission system according to the third embodiment. First, the vehicle 200 transmits a data request for requesting acquisition of data desired to be transmitted from the home server 100 to the center 320 (800). In response to the data request from the vehicle 200, the center 320 transmits the data request to the home server 100 (801). In response to the data request from the center 320, the home server 100 transmits all data to the center 320 (802).

  On the other hand, the vehicle 200 sequentially transmits vehicle information to the center 320 (803). Based on the vehicle information received from the vehicle 200, the center 320 predicts a route that the vehicle 200 will travel thereafter (804). Then, using the predicted route and the position information of the roadside devices 400, 410, and 420 previously held by the center 320, the roadside device that the vehicle 200 may pass by, that is, the roadside on which the data is to be transmitted. The machine is determined (805). Here, it is assumed that 400, 410, and 420 are determined as the data transmission destination.

  In addition, the center 320 predicts the time when the vehicle 200 moves from the roadside machine 400 to the roadside machine 410, and when the data transmitted from the roadside machine 400 is reproduced by the vehicle 200, the reproduction is performed from the roadside machine 410 to the next. The data is divided and processed so as not to be completed before the data is received, that is, according to the data reproduction status (806). For example, the center 320 performs transcoding to lower the bit rate, or when the data corresponds to a plurality of bit rates such as hierarchical coding, performs processing to extract data with a low bit rate.

  Next, the center 320 transmits the divided data to the roadside machine 400 (807). Further, the center 320 transmits the divided data to the roadside device 410 (808). Further, the center 320 transmits the divided data to the roadside machine 420 (809). Thereafter, when the vehicle 200 enters the communication area of the roadside device 400, the vehicle 200 transmits a data transmission request to the roadside device 400 (810). The roadside machine 400 transmits the divided data to the vehicle 200 in response to the data transmission request (811). When the transmission of the divided data is completed, the roadside machine 400 transmits a data transmission notification to the center 320 (812). On the other hand, in the vehicle 200, the reproduction of the received divided data is started (813).

  Based on the vehicle information sequentially sent from the vehicle 200, the center 320 performs division and processing of data to be transmitted to the roadside device 410 predicted to communicate with the vehicle 200 next (814). Then, the center 320 transmits the divided data subjected to the division and processing to the roadside device 410 (815).

  Next, when the vehicle 200 enters the communication area of the roadside device 410, the vehicle 200 transmits a data transmission request to the roadside device 410 (816). The roadside device 410 transmits the divided data to the vehicle 200 in response to the data transmission request (817). When the transmission is completed, the roadside device 410 transmits a data transmission notification to the center 320 (818).

  The center 320 divides and processes data to be transmitted to the roadside machine 420 predicted to communicate with the vehicle 200 next based on the vehicle information sequentially transmitted from the vehicle 200 (819). Then, the center 320 transmits the divided data subjected to the division and processing to the roadside machine 420 (820).

  Next, when entering the communication area of the roadside device 420, the vehicle 200 transmits a data transmission request to the roadside device 420 (821). The roadside machine 420 transmits the divided data to the vehicle in response to the data transmission request (822). When the transmission is completed, the roadside device 420 transmits a data transmission notification to the center 320 (823). In this example, transmission of all data to the vehicle 200 is completed at this point.

  Thereafter, the vehicle 200 notifies the center 320 that the reception of all data has been completed (824). In response to the notification from the vehicle 200, the center 320 notifies the home server 100 that the transmission of all data has been completed, and completes a series of data transmission (825).

  As described above, according to the data transmission system according to the third embodiment of the present invention, when data with a large file size is transmitted to a vehicle, the route on which the vehicle travels is predicted in advance and exists on the predicted route. The data to be transmitted to the roadside machine to be transmitted is divided and the data with the bit rate selected appropriately is transmitted, so the vehicle is interrupted so that the data of the largest file size is at hand. It is possible to reproduce the data without any problem.

  DESCRIPTION OF SYMBOLS 100 Home server, 200 Vehicle, 201, 202 Network interface, 203 Navigation system, 204 Vehicle information management part, 205 Travel history management part, 206 Direction indicator, 207 Vehicle speed sensor, 208 GPS, 209 coupling part, 210 Storage part, 211 Control unit, 300, 310, 320 center, 301, 302, 303, 311, 312, 313, 321, 322, 323 network interface, 304, 314, 324 prediction unit, 305, 316, 326 storage unit, 306, 317, 327 control unit, 315 division unit, 325 division processing unit, 400, 410, 420, 430, 330, 350 roadside unit, 401, 402 network interface, 403 vehicle priority determination unit, 404 storage unit, 405 control , 441 antenna, 442 a communication area, 500, 510, 520 network, 501,502,511,512,521,522,523,524,525,526,527 communication path.

Claims (12)

A center that holds the data,
A roadside machine installed beside the road,
A vehicle that transmits vehicle information to the center and communicates with the roadside machine;
A data transmission system in which the center predicts a route on which the vehicle travels based on vehicle information received from the vehicle, and transmits and holds data held by the roadside unit installed on the predicted route . The data transmission system according to claim 1, wherein the vehicle receives data held in the roadside device through communication with the roadside device. The vehicle uses the information representing at least one of the guide route, the vehicle position, the speed, the traveling direction, the instruction content of the direction indicator, and the traveling history of the vehicle presented by the navigation system mounted on the vehicle as the vehicle information. The data transmission system according to claim 1, wherein the data transmission system transmits the data to the network. The data transmission system according to any one of claims 1 to 3, wherein when the center recognizes that the route prediction has failed, the center re-predicts the route on which the vehicle travels. The data transmission system according to any one of claims 1 to 4, wherein the roadside machine holds all data to be transmitted to the vehicle. The data transmission system according to any one of claims 1 to 4, wherein the roadside unit holds a part of data obtained by dividing all data transmitted to the vehicle. The data transmission system according to claim 5 or 6, wherein the roadside device erases the stored data when a predetermined time elapses. 7. The data transmission system according to claim 6, wherein a part of the data held in the roadside machine is processed so that it cannot be restored to the original data unless all of the divided data are prepared. The data transmission system according to claim 6, wherein a part of the data held in the roadside machine is processed so that a bit rate differs according to a reproduction state of data in the vehicle. The data transmission system according to any one of claims 1 to 9, wherein the roadside device communicates with a vehicle having a high priority when communication is requested from a plurality of vehicles. 11. The data transmission system according to claim 10, wherein the roadside unit determines the priority based on a ratio of the data amount already received by the vehicle to the total data amount. The roadside machine, when sequentially reading the data received by the vehicle, determines the priority according to how far the reading position is from the final position of the data received by the vehicle. Item 11. The data transmission system according to Item 10.

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