JP2003152627A - Communication control method, terminal device and data distribution controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication control method, a terminal device and a data distribution controller in which data of comparatively large capacity can be exchanged with a wireless terminal moving at high speed along a road or a railroad track. SOLUTION: In the communication control method for the data distribution controller connected in a state enabling communication with a plurality of radio base stations to transmit information to the wireless terminal by using a communication system, in which a plurality of radio base stations are installed along the moving route of the wireless terminal and the data distribution controller is provided, on the basis of information transmitted by the wireless terminal, the location of the wireless terminal in future is predicted and on the basis of the predicted location of the wireless terminal at every time point and the install position of each of radio base stations or position or a radio zone to be formed, a communication time between each of radio base stations and the wireless terminal is predicted. In a timing based on the predicted communication time, information is transmitted from the data distribution controller to the specific radio base station.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control method, a terminal device and a data distribution control device for transmitting data to a wireless terminal that is moving by using an automobile or the like, and particularly to each wireless base station and wireless. It is used in a system with restrictions on the timing at which data can be transmitted to and from a terminal.

[0002]

2. Description of the Related Art For example, when a mobile phone network or PHS (Personal Handy Phone System) network is used as a communication means, a wireless zone (communicable range) of each wireless base station
Is relatively wide, and the wireless zones of adjacent wireless base stations often overlap with each other. Therefore, no matter where the wireless terminal is located, the wireless terminal and one of the wireless base stations are You can communicate between them.

On the other hand, the next-generation intelligent transportation system (IT
As a data communication technology expected to be used for S) wireless communication, DSRC (Narrow Area Communication: Dedicated Short)
t Range Communications) is known. In the case of DSRC, high-speed communication is possible, but the communicable range of each radio base station is very narrow.

[0004]

In data communication using a mobile phone network or a PHS network, each wireless base station has a wide communicable area (wireless zone), and switching of wireless base stations used for communication (handover) is also performed. Since technology is established, communication can be performed from any location.
However, since the communication speed is low in the mobile telephone network and the PHS network, it is not suitable for large capacity data communication.

When data communication is performed using DSRC, the communication speed is high, but the communicable area of each base station is narrow. Therefore, when a wireless terminal that communicates with a base station is installed in, for example, an automobile or a train and is moving at high speed, communication can be continued only for a very short time, and the wireless communication can be performed before the end of data transmission / reception. The terminal may go out of the coverage area of the base station of the communication partner and data communication may fail.

Further, since it is not possible to specify in advance which base station can communicate with a specific wireless terminal that is moving, a server that distributes a large amount of data to a wireless terminal is all of a large number of base stations. Have to send the same data to. That is, the server distributes useless data to a large number of base stations that do not transmit data to the wireless terminal, and the traffic of the communication network between the server and each base station increases more than necessary.

Therefore, when the DSRC is used, it is difficult to transmit a large amount of data to a wireless terminal moving at high speed. Further, in data communication using artificial satellites, it is technically possible to perform large-capacity data communication with a wireless terminal moving at high speed. However, the unit price per satellite is high, and it is actually difficult to allocate a large line capacity to communication with one wireless terminal.

The present invention provides a communication control method, a terminal device, and a data distribution control device capable of transmitting a relatively large amount of data with a wireless terminal that moves at high speed along a road or a railroad track. The purpose is to

[0009]

According to a first aspect of the present invention, a plurality of radio base stations are installed along a moving path of a radio terminal at intervals larger than respective radio zones, and can communicate with a plurality of radio base stations. A communication control method for transmitting information to the wireless terminal by the data distribution control apparatus using a communication system provided with a data distribution control apparatus connected in a wireless state, wherein the wireless terminal transmits Based on the information to predict the future position of the wireless terminal, based on the predicted position of each time of the wireless terminal and the installation position of each wireless base station or the position of the wireless zone to be formed, each wireless base Characterized by predicting a communication available time between a station and the wireless terminal, and transmitting information from the data distribution control device to a specific wireless base station at a timing based on the predicted communication available time.

According to a first aspect of the present invention, a plurality of wireless base stations installed along the moving route of the wireless terminal are installed at intervals larger than the respective wireless zones, and each wireless base station wirelessly operates like DSRC. Since it is assumed that the zone is small, the moving wireless terminal cannot perform communication except when it approaches any one of the wireless base stations. For example,
Assuming the case where a wireless terminal is installed in an automobile that moves at a constant speed along a specific road, if the current position and moving speed of the wireless terminal at a certain point in time are known, future information based on those information will be used. The position of the wireless terminal at each time can be predicted. The position of each wireless base station is fixed and can be grasped in advance.

Therefore, by comparing the predicted position of the wireless terminal at each time with the position of each wireless base station or the position of the wireless zone formed by each wireless base station, it becomes possible to communicate with the wireless terminal. It is possible to specify the wireless base station that becomes and to predict the time when communication is possible. For this reason, if the data distribution control device that distributes data transmits data only to a specific wireless base station that becomes communicable before the communicable time, the wireless base station and the wireless base station can communicate at a scheduled time. A communication line can be established with the terminal and data can be transmitted from the wireless base station to the wireless terminal.

Regarding the establishment of the communication line between the wireless base station and the wireless terminal, it is sufficient to simply transmit the data from the wireless base station at the predicted time.
The same control as C may be adopted. Claim 2 is claim 1
In the communication control method, the wireless terminal transmits to the wireless base station a data distribution request including at least information on the current position, moving speed, and traveling direction of the wireless terminal, and the wireless base station transmits the data to the wireless terminal. The data delivery request received from the device is transferred to the data delivery control device, and the data delivery control device predicts the future position of the wireless terminal based on the received data delivery request.

According to the second aspect, it is assumed that the wide area wireless base station is not used and the wireless terminal transmits a data distribution request to the wireless base station. Therefore,
The wireless terminal can send the data distribution request only when the wireless terminal approaches any one of the wireless base stations. Since the data distribution request transmitted by the wireless terminal includes information on the current position, moving speed, and traveling direction of the wireless terminal, the position of the wireless terminal at each future point in time can be predicted based on these information. it can.

According to a third aspect of the present invention, a plurality of wireless base stations are installed along the moving path of the wireless terminal at intervals larger than the respective wireless zones, and are connected to the plurality of wireless base stations in a communicable state. A communication control method for transmitting information to the wireless terminal, wherein the data delivery control device uses a communication system provided with a data delivery control device,
When a wide area wireless base station having a larger wireless zone than the wireless base station can be used, data including at least information on the current position and moving speed of the wireless terminal from the wireless terminal to the wide area wireless base station Send a delivery request,
The wide area wireless base station transfers a data distribution request received from the wireless terminal to the data distribution control device, and the data distribution control device predicts a future position of the wireless terminal based on the received data distribution request. It is characterized by

In claim 3, a mobile phone network or PHS is used.
It is assumed that a wide area wireless base station having a larger wireless zone than the wireless base station, such as a network base station, can be used at the same time. Therefore, even when the wireless terminal is moving at high speed, it is possible to perform communication at any time between the wireless terminal and the wide area wireless base station. Therefore, the wireless terminal transmits a data distribution request to the wide area wireless base station. Further, this data distribution request includes information on the current position and moving speed of the wireless terminal. The position of the wireless terminal at each future time point can be predicted based on these pieces of information.

When transmitting position information at a plurality of time points, the moving direction can be identified from the change in position. According to a fourth aspect of the present invention, in the communication control method according to the second or third aspect, the data distribution control device sets the future position of the wireless terminal on a specific road or on a specific track based on the received data distribution request. The feature is that the prediction is limited to the figure.

In claim 4, it is assumed that the wireless terminal moves by a car or a train along a specific road such as an expressway or a railroad track. By predicting a future position only on a specific road or on a route map of a specific railroad, the prediction process becomes easy. According to a fifth aspect of the present invention, when a plurality of wireless base stations are installed along a specific travel route at intervals larger than those of the respective wireless zones, wireless communication is possible with the wireless base stations. In a terminal device including means, position detecting means for detecting the current position of the terminal itself or a vehicle equipped with the terminal,
A moving speed detecting means for detecting a moving speed of the terminal itself or a vehicle equipped with the terminal, a moving direction detecting means for detecting a moving direction of the terminal itself or a vehicle equipped with the terminal, and the position detecting means as a data distribution request. Transmission control means for transmitting information including the detected position information, the moving speed detected by the moving speed detecting means, and the moving direction detected by the moving direction detecting means to a specific data distribution control device via the wireless base station. And is provided.

The terminal device according to claim 5 can be used when implementing the method according to claim 2. That is, since the information transmitted by this terminal device includes the current position, moving speed, and moving direction of the terminal device, the position of the terminal device at each future point in time can be predicted. The information transmitted by the terminal device is transmitted to the data distribution control device via a communicable radio base station.

According to a sixth aspect of the present invention, in a terminal device, when a plurality of narrow area wireless base stations are installed along a specific moving route with a gap larger than each wireless zone, In a terminal device comprising a first wireless communication means capable of wireless communication between two wireless devices, a second wireless device capable of wireless communication with a wide area wireless base station having a larger wireless zone than the narrow area wireless base station. The communication means, the position detecting means for detecting the current position of the terminal itself or a vehicle equipped with the terminal, the moving speed detecting means for detecting the moving speed of the terminal itself or the vehicle equipped with the terminal, and the terminal itself or the same are mounted. Moving direction detecting means for detecting a moving direction of the vehicle, position information detected by the position detecting means as a data distribution request, moving speed detected by the moving speed detecting means, and moving direction detection Stage is characterized in that a transmission control means for transmitting information including the moving direction detected specific data distribution control device addressed via the wide area radio base station.

The terminal device according to claim 6 can be used when performing the method according to claim 3. That is, since the information transmitted by this terminal device includes the current position, moving speed, and moving direction of the terminal device, the position of the terminal device at each future point in time can be predicted. The information transmitted by the terminal device is transmitted by the second wireless communication means to the specific data distribution control device via the wide area wireless base station.

According to a seventh aspect of the present invention, there is provided a data distribution control device for distributing data from a wireless terminal when a plurality of wireless base stations are installed along a moving route of the wireless terminal with an interval larger than each wireless zone. In a data distribution control device that distributes data according to a request to the wireless terminal via the wireless base station, based on information of a current position, a moving speed and a moving direction included in a data distribution request of the wireless terminal, Position prediction means for predicting the future position of the wireless terminal, based on the predicted position of each time of the wireless terminal and the installation position of each wireless base station or the position of the wireless zone to be formed, each wireless base station and the above A time predicting unit that predicts a communication available time with the wireless terminal and a transmission control unit that transmits information to a specific wireless base station at a timing based on the predicted communication available time. And wherein the digit.

The data distribution control device of claim 7 can be used when the methods of claims 1, 2 and 3 are carried out. That is, it is possible to specify the data transmission destination radio base station based on the information transmitted from the radio terminal and transmit the data to the radio base station at an appropriate timing. The data distribution control device according to claim 8, wherein a plurality of wireless base stations are installed along the moving route of the wireless terminal at intervals larger than those of the respective wireless zones, the wireless zone of the wireless base station is larger than that of the wireless base station. When receiving a data distribution request from a wireless terminal via a large wide area wireless base station,
In a data distribution control device that distributes data according to a request to the wireless terminal via the wireless base station, based on information of a current position, a moving speed and a moving direction included in a data distribution request of the wireless terminal, Position prediction means for predicting the future position of the wireless terminal, based on the predicted position of each time of the wireless terminal and the installation position of each wireless base station or the position of the wireless zone to be formed, each wireless base station and the above It is characterized in that a time predicting means for predicting a communicable time with the wireless terminal and a transmission control means for transmitting information to a specific wireless base station at a timing based on the predicted communicable time are provided.

In claim 8, it is assumed that the data distribution control device receives the data distribution request from the wireless terminal via the wide area wireless base station. The data distribution control device according to claim 8 can be used when the method according to claims 1, 2, and 3 is carried out. That is, it is possible to specify the data transmission destination radio base station based on the information transmitted from the radio terminal and transmit the data to the radio base station at an appropriate timing.

According to a ninth aspect of the present invention, in the data distribution control device according to the seventh or eighth aspect, the position predicting means determines the future position of the wireless terminal on a specific road or on a specific road based on the received data distribution request. The feature is that the prediction is limited to the line map of the line. In claim 9, it is assumed that the wireless terminal moves by a car or a train along a specific road such as an expressway or a railroad track. By predicting a future position only on a specific road or on a route map of a specific railroad, the prediction process becomes easy.

According to a tenth aspect of the present invention, in the data distribution control device according to the seventh or eighth aspect, when transmitting data larger than the amount of information that can be transmitted between one radio base station and the radio terminal. Data is further divided into a plurality of parts, and data distribution means for distributing destinations of the divided data to a plurality of radio base stations is further provided. When the moving speed of the wireless terminal is high, the communicable time during which the wireless terminal passes near one wireless base station becomes very short. Therefore, even when data is transmitted at high speed, it is possible that only a part of the data to be transmitted can be transmitted.

In the tenth aspect, when a large amount of data is transmitted, the data is divided into a plurality of pieces and the destinations of the divided data are distributed to the plurality of wireless base stations. It is possible to repeatedly communicate with the station intermittently and deliver a large amount of data. According to an eleventh aspect of the present invention, in the data distribution control device according to the tenth aspect, the data distribution unit determines the amount of information that can be transmitted between one wireless base station and the wireless terminal based on a moving speed of the wireless terminal. It is characterized by doing.

The length of time during which communication is possible between the wireless terminal and one wireless base station changes according to the moving speed of the wireless terminal. Therefore, by determining the amount of information that can be transmitted between one wireless base station and the wireless terminal based on the moving speed, it is possible to optimize the amount of data distributed from one wireless base station. , The time required for data distribution can be shortened when a large amount of data is distributed.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) 1 of a communication control method, a terminal device and a data distribution control device of the present invention
One embodiment will be described with reference to FIGS. This form corresponds to claim 1, claim 3, claim 4, claim 6 and claim 8 to claim 11.

FIG. 1 is a sequence diagram showing the operation of the system in this mode. FIG. 2 is a block diagram showing the configuration of the system of this mode. FIG. 3 is a block diagram showing a configuration example of an in-vehicle wireless terminal. FIG. 4 is a schematic diagram showing a configuration example of a data distribution request transmitted by the in-vehicle wireless terminal of this embodiment. FIG. 5 is a flowchart showing the operation of the data distribution control device.

In this embodiment, the second wireless communication means, the position detection means, the moving speed detection means, the moving direction detection means and the transmission control means of claim 7 are respectively the wide area wireless communication device 1
2. It corresponds to the current position detector 18, the moving speed detector 16, the moving direction detector 17, and the terminal control unit 110.
Further, the position predicting means, the time predicting means, and the transmission control means of claim 8 respectively include steps S14, S17 and S1
Corresponds to 8. The data distribution means of claim 10 corresponds to step S15.

In this embodiment, a system as shown in FIG. 2 is assumed. That is, a data distribution request is transmitted from the in-vehicle wireless terminal 10 mounted on an automobile running on a road such as a highway. In response to this request, the data distribution control device 32 retrieves the corresponding data from the database 33 and distributes it to the in-vehicle wireless terminal 10. Many narrow area base stations 20 (1), 2 along the road on which this car runs
0 (2), 20 (3), ... Are installed with a predetermined interval or more. Here, each narrow area base station 20 has a DSRC
Since it is assumed that communication is performed with the vehicle-mounted wireless terminal 10 using the above technology, the size of the narrow area wireless zone 21 (communicable range) formed by each narrow area base station 20 is very small. .

In addition, narrow area base stations 20 adjacent to each other
Are installed at larger intervals than the narrow area wireless zone 21 formed by them. Therefore, continuous communication cannot be performed between the onboard wireless terminal 10 and each narrow area base station 20, and communication is possible only when the onboard wireless terminal 10 approaches any of the narrow area base stations 20. Become. In this mode, the in-vehicle wireless terminal 10 has a satellite communication function, and wirelessly communicates with the wide area base station 30 via the satellite 31 in the wide area wireless zone 36 much larger than the narrow area wireless zone 21. Can communicate. That is, the in-vehicle wireless terminal 10 and the wide area base station 30 can always communicate with each other as needed.

It is also conceivable to use a radio base station of a mobile phone network or a PHS network instead of satellite communication. Further, a plurality of wide area base stations 30 may be provided and any one of the wide area base stations 30 may be selectively used. All the narrow area base stations 20 and the wide area base stations 30 are connected to the data distribution control device 32 via a wired communication network 35. Also,
A database 33 is connected to the data distribution control device 32.

As shown in FIG. 3, the in-vehicle wireless terminal 10 has a D
SRC wireless communication device 11, wide area wireless communication device 12, input unit 13, display unit 14, storage unit 15, moving speed detector 16,
A moving direction detector 17, a current position detector 18, a road discriminator 19, and a terminal control unit 110 are provided. DSR
C wireless communication device 11 is connected to each narrow area base station 20 by DS.
It is a communication device that can perform RC communication. In addition, the wide area wireless communication device 12 transmits the wide area base station 30 via the satellite 31.
It is a communication device capable of performing wireless communication with.

The moving speed detector 16 detects the moving speed of the terminal itself or a vehicle equipped with the terminal. Also,
The traveling direction detector 17 outputs information indicating whether the traveling direction is an up / down direction of the road or information indicating an azimuth of the traveling direction. The road discriminator 19 is used for the in-vehicle wireless terminal 10
The road identification number (R3) representing the road on which the vehicle equipped with is running is detected. Further, the current position detector 18 detects the current position (R4) on the road on which the vehicle equipped with the in-vehicle wireless terminal 10 is traveling.

The detection of the road and the current position can be obtained by, for example, communicating with a beacon installed on the road or calculating the position using a GPS satellite. The storage unit 15 holds in advance information of a unique terminal identification number (R2) assigned in advance for each terminal. The storage unit 15 also temporarily stores information input from the input unit 13 and the like.

The input unit 13 is used to input the data identification number (R1) of the data required by the user and the information (R7) indicating the current destination. The display unit 14 displays the content of data distributed from the data distribution control device 32, for example. When data distribution is desired to be distributed to the data distribution control device 32, the in-vehicle wireless terminal 10 transmits a predetermined data distribution request. In this example, the information as shown in FIG. 4 is transmitted as a data distribution request.

That is, in the data distribution request, the data identification number R1, the terminal identification number R2, the road identification number R3, the current position R4, the moving speed R5, the moving direction R6 and the destination R7.
Information is included. The data distribution control device 32 holds in advance a road map regarding major roads such as highways, the installation positions of the narrow area base stations 20 arranged on the road, and information on the narrow area wireless zones 21 to be formed. The narrow area base station 20 manages information such as the status of data waiting to be delivered and the data transfer rate.

The data distribution control device 32 controls the vehicle-mounted wireless terminal 1 based on the information managed by itself and the information contained in the data-distribution request input from the vehicle-mounted wireless terminal 10.
Data distribution control for 0 is performed. Next, the operation of the entire system will be described with reference to FIG. If you want to manually access the information that users on your car need,
Alternatively, in the case of automatically acquiring information, it is necessary to input the identification number of the data into the in-vehicle wireless terminal 10.

In step S11, the data identification number (R1)
Is input, the in-vehicle wireless terminal 10 generates a data distribution request addressed to the data distribution control device 32 in step S12,
This request is transmitted to the wide area base station 30 using the wide area wireless communication device 12. The wide area base station 30 is an in-vehicle wireless terminal 1.
When the data distribution request from 0 is received via the satellite 31, this data distribution request is transferred to the data distribution control device 32 via the wired communication network 35.

Data distribution from the data distribution control device 32 to the in-vehicle wireless terminal 10 is performed using the wireless communication function of the narrow area base station 20. However, unless the onboard wireless terminal 10 approaches each narrow area base station 20 and enters the narrow area wireless zone 21, communication cannot be actually performed. Also,
When the same data is transmitted from the data distribution control device 32 to all the narrow area base stations 20, the traffic is significantly increased.

Therefore, the data distribution control device 32 specifies one or a plurality of narrow area base stations 20 that can be used for actual communication, and the data distribution control device 32 ensures that data distribution can be ensured. The timing of transmitting data to the station 20 is appropriately determined. Step S1
At 4, the travel route of the vehicle-mounted wireless terminal 10 is predicted based on the information included in the received data distribution request from the vehicle-mounted wireless terminal 10 and the road map information, and the position at each time point in the future is predicted.

When the specific narrow area base station 20 to be used for data distribution has a large amount of data waiting to be transmitted, or when the data distribution control device 32 has a large amount of data to be distributed, the in-vehicle wireless terminal is provided. There is a possibility that all the data cannot be transmitted from the narrow area base station 20 to the vehicle-mounted wireless terminal 10 while the vehicle 10 passes in the vicinity of one narrow area base station 20.

In such a case, the data transmitted by the data distribution control device 32 is divided into a plurality of pieces in step S15. Further, in step S16, each narrow area base station 20 assigned to the destination is determined so that the respective destinations (relay stations) of the divided data are distributed to the plurality of narrow area base stations 20.

In order to reliably deliver the data from the specific narrow area base station 20 to the in-vehicle wireless terminal 10, before the time when the narrow area base station 20 starts transmitting the data,
It is necessary to complete the data transfer from the data distribution control device 32 to the narrow area base station 20.

In step S17, each narrow area base station 20
Determines a scheduled time for data transmission from the onboard wireless terminal 10. In step S18, data is transmitted to the narrow area base station 20 before the scheduled data transmission time of step S17. When the data is divided in step S15, a part of the divided data is transmitted to each of the plurality of narrow area base stations 20 as shown in FIG.

The narrow area base station 20 which has received the data transmits the data to the in-vehicle wireless terminal 10 which is the data request source at the scheduled time (step S19). The existing DSRC technology may be used for the communication timing and protocol between the narrow area base station 20 and the in-vehicle wireless terminal 10. A more detailed operation of the data distribution control device 32 will be described with reference to FIG.

In step S31, the information registered in advance in the data distribution control device 32 is read to grasp the position of each narrow area base station 20 and the contents of the road map. In step S32, based on the current position R4, the moving speed R5, and the moving direction R6 included in the data distribution request input from the vehicle-mounted wireless terminal 10, the vehicle-mounted wireless terminal 10 on the specific road corresponding to the road identification number R3. The movement route and the position of each point in the future are predicted. Further, based on the position of each narrow area base station 20 and the predicted position of the in-vehicle wireless terminal 10, a scheduled communication start time (in-vehicle wireless communication) that enables communication between the narrow area base station 20 and the in-vehicle wireless terminal 10 will be performed. The time ts at which the terminal 10 enters one wireless zone) ts is calculated for each narrow area base station 20.

When the road ahead of the on-vehicle wireless terminal 10 is branched, a plurality of candidates are detected as the predicted travel route. In such a case, the travel route candidates can be narrowed down by using the information of the destination R7 included in the data distribution request. That is, the number of moving route candidates can be reduced by examining the correlation between a plurality of branched roads and the destination.

When a plurality of moving routes are detected, the same data may be transmitted from the data distribution control device 32 to the narrow area base stations 20 existing on the respective routes. In step S33, one narrow area base station 20 used for data distribution to the vehicle-mounted wireless terminal 10 is used.
Select. The narrow-area base station 20 selected first is the narrow-area base station 20 installed at the position closest to the on-vehicle wireless terminal 10 on the moving path of the on-vehicle wireless terminal 10 in the traveling direction.

When step S33 is executed a plurality of times, the narrow area base station 2 whose installation position is close to the in-vehicle wireless terminal 10
It is selected in order from 0. In step S34, between the selected narrow area base station 20 and the in-vehicle wireless terminal 10 based on the size of the wireless zone of the one narrow area base station 20 selected in step S33 and the moving speed R5 of the in-vehicle wireless terminal 10. The length of the communicable period Tc is calculated. That is,
A time equivalent to the time required for the in-vehicle wireless terminal 10 to pass through the wireless zone of the selected narrow area base station 20 is obtained.

In step S35, the data identification number R1
The amount (size) A1 of data requested by the in-vehicle wireless terminal 10 is grasped by. In step S36, the capacity A2 of the transmission waiting data in the narrow area base station 20 selected in step S33 is grasped. For example, communication is performed with the narrow area base station 20, and the current waiting data capacity A
Inquire 2.

In step S37, the data capacity (A1 +
Identify whether A2) is large enough to be transmitted. That is, the communication speed between the narrow area base station 20 and the in-vehicle wireless terminal 10 is grasped, and the communicable period T obtained in step S34 is calculated.
Whether or not all data of size (A1 + A2) can be transmitted during c is identified.

If the data capacity (A1 + A2) is too large, the process proceeds from step S37 to S38 and the data is divided. That is, since the capacity A1 of the data to be transmitted from the data distribution control device 32 is too large, step S3
Only a part of the divided data is assigned to one narrow area base station 20 selected in 3. In order to process the rest of the divided data, the process returns from step S38 to S33 to select the next narrow area base station 20 and allocate the rest of the data. When the allocation of all data to each narrow area base station 20 is completed, the process proceeds from step S37 to S39.

In step S39, the transmission waiting data transmission end scheduled time t2 is grasped for each narrow area base station 20 used for data distribution to the vehicle-mounted wireless terminal 10.
For example, the scheduled communication start time ts obtained in step S32
Can be obtained as the time when the required transmission time corresponding to the capacity A2 of the data waiting to be transmitted has elapsed. Step S
At 40, the requested data is retrieved from the database 33, the data is divided as necessary, and each data is distributed to each narrow area base station 20 selected at step S33 at a predetermined time t1. Control device 32
Send from

The time t1 is before the scheduled data transmission end time t2 at the transmission destination narrow area base station 20. Also, the time t1 is set so that the data transmission to the narrow area base station 20 can be completed before the scheduled data transmission end time t2.
Is determined. When the in-vehicle wireless terminal 10 reaches the wireless zone of the narrow area base station 20, the transmission waiting data held in the narrow area base station 20 is first transmitted from the narrow area base station 20. Also, before the time (t2) when the transmission of the data waiting to be transmitted is completed, the data requested by the in-vehicle wireless terminal 10 is transferred from the data distribution control device 32 to the narrow area base station 20 and added to the data waiting to be transmitted. To be done.

Further, the capacity of the data added to the transmission waiting data on the narrow area base station 20 is set to a size that can be transmitted while the on-vehicle wireless terminal 10 passes through the wireless zone of the corresponding narrow area base station 20. It is divided. Therefore, it is possible to prevent the in-vehicle wireless terminal 10 from going out of the wireless zone of the narrow area base station 20 before the data transmission from each narrow area base station 20 is completed.

(Second Embodiment) One embodiment of the communication control method, terminal device and data distribution control device of the present invention will be described with reference to FIGS. 6 and 7. This form is defined in claim 1, claim 2, claim 4, claim 5,
It corresponds to claim 7 and claims 9 to 11. FIG. 6 is a sequence diagram showing the operation of the system in this mode. FIG. 7 is a block diagram showing the configuration of the system of this mode. This form is a modification of the first embodiment. The description of the same parts as those in the first embodiment will be omitted.

As shown in FIG. 7, in this embodiment, it is assumed that the in-vehicle wireless terminal 10 is installed in a train or the like traveling on a track. Further, in response to a data distribution request from the in-vehicle wireless terminal 10, the data distribution control device 32 distributes data to the in-vehicle wireless terminal 10 to transmit information to passengers. In addition, a large number of narrow-area base stations 2 along the line on which the train moves.
0 (1), 20 (2), 20 (3), ... Are installed with a predetermined interval or more. Here, each narrow area base station 20
Assumes that communication is performed with the vehicle-mounted wireless terminal 10 using the DSRC technology, so the size of the narrow area wireless zone 21 (communicable range) formed by each narrow area base station 20 is extremely small. Small. Each narrow area base station 20 has an identification number.

Also, the narrow area base stations 20 adjacent to each other
Are installed at larger intervals than the narrow area wireless zone 21 formed by them. Therefore, continuous communication cannot be performed between the onboard wireless terminal 10 and each narrow area base station 20, and communication is possible only when the onboard wireless terminal 10 approaches any of the narrow area base stations 20. Become.

Since the in-vehicle wireless terminal 10 can communicate only with any of the narrow area base stations 20, the in-vehicle wireless terminal 10 transmits a data distribution request to the narrow area base station 20 in this embodiment. The in-vehicle wireless terminal 10 is equipped with devices for detecting the moving speed and moving direction of the train, the running track, and the current position on the track. Further, the in-vehicle wireless terminal 10 holds the identification number of the train in which it is installed and the identification number of the vehicle.

In this embodiment, the data distribution control device 32 holds information such as a route map of railroad tracks, a train operation schedule, and installation positions of the narrow-area base stations 20. Similarly to the first embodiment, when the data distribution control device 32 receives the data distribution request from the in-vehicle wireless terminal 10, the data distribution control device 32 predicts the movement route of the in-vehicle wireless terminal 10 and the position at each time point in the future, and the in-vehicle wireless terminal 10 is predicted. Predict the time at which 10 and any of the narrow area base stations 20 can communicate. In addition, the narrow area base station 20 to be used for data distribution is determined by referring to the status of the data waiting to be transmitted from each narrow area base station 20, and the data is transferred from the data distribution control device 32 to the narrow area base station 20. Determine the scheduled time to do. If the amount of data to be distributed is large, the data is divided and distributed to a plurality of narrow area base stations 20.

A user who desires data distribution inputs an identification number of desired data to the in-vehicle wireless terminal 10. In this case, the process of the in-vehicle wireless terminal 10 proceeds from step S21 to S22 as shown in FIG.
It waits until 0 becomes possible to communicate with any of the narrow area base stations 20. When a vehicle equipped with the in-vehicle wireless terminal 10 passes through the wireless zone of the nearest narrow area base station 20,
The in-vehicle wireless terminal 10 determines the narrow area base station 20 in step S22.
To send a data distribution request to.

This data distribution request contains at least the data identification number, vehicle identification number, and moving speed information. By including information such as the current position in the data distribution request, the future position can be predicted more accurately.

The narrow area base station 20 having received the data distribution request transfers the received data distribution request to the data distribution control device 32 as it is through the wired communication network 35. The data distribution control device 32 predicts the moving route and the position of the vehicle by calculation based on the information included in the received data distribution request, the route map of the track, and the operation schedule of the train (S23).

If the requested data is larger than the size that can be transmitted by using one narrow area base station 20, the data distribution control device 32 divides the data and divides the data into a plurality of narrow area base stations. It is distributed to the stations 20 (S24). Regarding the narrow area base station 20 used for data distribution, the size of data allocated to each narrow area base station 20, and the time of transmission from the data distribution control device 32 to the narrow area base station 20, the movement route predicted in step S23, the vehicle-mounted It is determined based on the future position of the wireless terminal 10, the transmission end time of the transmission waiting data of each narrow area base station 20, and the like.

The data distribution control device 32 acquires the requested data from the database 33, divides it into the size determined in step S24, and transmits each data to the allocated narrow area base station 20 in step S27. To do. The transmission timing from the data distribution control device 32 to the narrow area base station 20 is before the transmission end time of the transmission waiting data in the narrow area base station 20.

[0068]

According to the present invention, even when a plurality of wireless base stations installed along a moving route such as a road have a small communication area and wireless terminals can communicate only at intermittent timings. Since the moving route and the position of the wireless terminal are predicted, the communication can be efficiently performed and the data can be distributed. In addition, it is possible to deliver a large amount of data even when the wireless terminal moves at high speed.

[Brief description of drawings]

FIG. 1 is a sequence diagram showing an operation of a system according to a first exemplary embodiment.

FIG. 2 is a block diagram showing a configuration of a system according to the first embodiment.

FIG. 3 is a block diagram showing a configuration example of an in-vehicle wireless terminal.

FIG. 4 is a schematic diagram showing a configuration example of a data distribution request transmitted by the vehicle-mounted wireless terminal according to the first embodiment.

FIG. 5 is a flowchart showing an operation of the data distribution control device.

FIG. 6 is a sequence diagram showing an operation of the system according to the second exemplary embodiment.

FIG. 7 is a block diagram showing a configuration of a system according to a second embodiment.

[Explanation of symbols]

10 In-vehicle wireless terminal 11 DSRC wireless communication device 12 Wide area wireless communication device 13 Input section 14 Display 15 memory 16 Moving speed detector 17 Moving direction detector 18 Current position detector 19 Road discriminator 20 Narrow area base station 21 Narrow area wireless zone 30 Wide Area Base Station 31 satellites 32 data distribution control device 33 Database 35 Wired communication network 36 Wide Area Wireless Zone 110 terminal control unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinya Nogami             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F term (reference) 5K033 AA01 BA06 DA17 DA19 DB16                 5K067 AA21 BB21 BB41 BB43 EE02                       EE07 EE10 EE13 EE44 EE57                       FF03 GG01 JJ53

Claims (11)

[Claims] 1. A data distribution control in which a plurality of wireless base stations are installed along a moving path of a wireless terminal at intervals larger than respective wireless zones, and are connected in a communicable state with the plurality of wireless base stations. A communication control method for the data distribution control device to transmit information to the wireless terminal using a communication system provided with a device, wherein the wireless terminal is based on information transmitted by the wireless terminal. The future position of the wireless terminal can be predicted, and the wireless terminal can communicate with the wireless terminal based on the predicted position of the wireless terminal at each time and the position of each wireless base station or the position of the wireless zone formed. A communication control method comprising predicting a time and transmitting information from the data distribution control device to a specific wireless base station at a timing based on the predicted available communication time. 2. The communication control method according to claim 1, wherein the wireless terminal transmits, to the wireless base station, a data distribution request including at least information about a current position, a moving speed, and a traveling direction of the wireless terminal, The wireless base station transfers the data distribution request received from the wireless terminal to the data distribution control device, and the data distribution control device predicts a future position of the wireless terminal based on the received data distribution request. A characteristic communication control method. 3. A data distribution control in which a plurality of wireless base stations are installed along a moving path of a wireless terminal at intervals larger than each wireless zone, and are connected in a communicable state with the plurality of wireless base stations. A communication control method for the data distribution control device to transmit information to the wireless terminal using a communication system provided with a device, the wide area wireless base having a wireless zone larger than that of the wireless base station. When a station is available, the wireless terminal transmits to the wide area wireless base station a data distribution request including at least information on the current position and moving speed of the wireless terminal, and the wide area wireless base station The data distribution request received from the wireless terminal is transferred to the data distribution control device, and the data distribution control device determines the future position of the wireless terminal based on the received data distribution request. Communication control method characterized by prediction. 4. The communication control method according to claim 2 or 3, wherein the data distribution control device determines a future position of the wireless terminal on a specific road or on a specific track based on the received data distribution request. A communication control method characterized in that prediction is limited to the figure. 5. A radio communication capable of performing radio communication with a radio base station when a plurality of radio base stations are installed along a specific travel route at intervals larger than those of the respective radio zones. In a terminal device provided with means, a position detecting means for detecting the current position of the terminal itself or a vehicle equipped with the same, a moving speed detecting means for detecting the moving speed of the terminal itself or a vehicle equipped with the terminal, and the terminal itself or its A moving direction detecting means for detecting a moving direction of a vehicle equipped with a vehicle, and position information detected by the position detecting means, a moving speed detected by the moving speed detecting means and a moving direction detecting means as a data distribution request. A terminal device, comprising: transmission control means for transmitting information including a moving direction to a specific data distribution control device via the radio base station. 6. When a plurality of narrow area wireless base stations are installed along a specific travel route at intervals larger than those of each wireless zone, wireless communication is performed with the narrow area wireless base stations. A terminal device comprising a possible first wireless communication means, a second wireless communication means capable of wireless communication with a wide area wireless base station having a larger wireless zone than the narrow area wireless base station, and the terminal itself. Alternatively, a position detecting means for detecting the current position of a vehicle equipped with the same, a moving speed detecting means for detecting a moving speed of the terminal itself or a vehicle equipped with the terminal, and a moving direction of the terminal itself or a vehicle equipped with the terminal. Moving direction detecting means, and data distribution request, position information detected by the position detecting means, moving speed detected by the moving speed detecting means, and movement detected by the moving direction detecting means. Terminal device characterized in that a transmission control means for transmitting information including the direction to the wide area radio base station specific data distribution control device addressed through. 7. When a plurality of wireless base stations are installed along a moving route of the wireless terminal at intervals larger than those of each wireless zone, the wireless terminal transmits data according to a data distribution request from the wireless terminal. In a data distribution control device that distributes to a wireless terminal via a base station, a future position of the wireless terminal is predicted based on information of a current position, a moving speed, and a moving direction included in a data distribution request of the wireless terminal. Based on the predicted position of the wireless terminal at each time point and the installation position of each wireless base station or the position of the wireless zone to be formed, the communicable time of each wireless base station and the wireless terminal. A data distribution characterized by comprising a time prediction means for predicting and a transmission control means for transmitting information to a specific radio base station at a timing based on the predicted communicable time. Signal control device. 8. A wide area wireless base having a larger wireless zone than the wireless base station when a plurality of wireless base stations are installed along the moving route of the wireless terminal at intervals larger than those of the respective wireless zones. When receiving a data distribution request from a wireless terminal via a station, in a data distribution control device that distributes data according to the request to the wireless terminal via the wireless base station, in the data distribution request of the wireless terminal Position prediction means for predicting a future position of the wireless terminal based on the present position, moving speed, and moving direction information, and predicted position of the wireless terminal at each time and installation position of each wireless base station Alternatively, a time prediction unit that predicts a communicable time between each wireless base station and the wireless terminal based on the position of the formed wireless zone and a timing based on the predicted communicable time is specified. A data distribution control device comprising: a transmission control means for transmitting information to a fixed wireless base station. 9. The data distribution control device according to claim 7 or 8, wherein the position predicting means determines the future position of the wireless terminal based on the received data distribution request on a specific road or on a specific track. A data distribution control device characterized in that prediction is limited to the figure. 10. The data distribution control device according to claim 7 or 8, wherein when data larger than the amount of information that can be transmitted between one radio base station and the radio terminal is transmitted, the data is transmitted. A data distribution control device, further comprising data distribution means for dividing the data into a plurality of destinations and distributing the divided data destinations to a plurality of wireless base stations. 11. The data distribution control device according to claim 10, wherein the data distribution unit determines the amount of information that can be transmitted between one wireless base station and the wireless terminal based on a moving speed of the wireless terminal. A data distribution control device characterized by: