WO2014147953A1

WO2014147953A1 - Communication system

Info

Publication number: WO2014147953A1
Application number: PCT/JP2014/000844
Authority: WO
Inventors: 雄太清水; 啓文植田
Original assignee: 日本電気株式会社
Priority date: 2013-03-21
Filing date: 2014-02-19
Publication date: 2014-09-25
Also published as: JPWO2014147953A1; JP5896080B2

Abstract

This communication terminal is provided with a communication unit which performs wireless communication, a data storage unit which stores the data to be sent to receiving terminals, a line information storage unit which stores line information, which is information relating to a line configured from transmission terminals, a data partition and distribution determining unit which determines a partition method and a distribution method of data on the basis of the line information, and a data partitioning and distributing unit which partitions the data into multiple sets of partial data according to the determined partition method and transmits bundles by wireless communication to multiple transmission terminals that are the distribution destination determined by the determined distribution method, said bundles including partial data obtained by partitioning, destination information in which the receiving terminals are set as destinations, and relation information about the relation between the partial data and the pre-partitioned data.

Description

Communications system

The present invention relates to a communication system, a communication method, a communication terminal, and a program.

DTN (Delay / Disruption Tolerant Network) is known as a communication method for realizing highly reliable data transfer in a poor communication environment where a physical link between communication terminals does not always exist. In DTN, data to be transferred is broken down into smaller units called bundles, and transfer processing to the destination communication terminal is performed in bundle units. In addition, when there is no connection to the next hop, a store-and-forward method is adopted that waits for transfer while accumulating data at the communication terminal at the relay point, and transfers data when connected to the next hop. Is done. Then, the destination communication terminal combines the received bundles to reconstruct the entire data. Details of DTN are described in Non-Patent Document 1.

Also, the following methods are known as routing methods for transmitting and receiving data between DTN communication terminals. One is an epidemic method in which individual communication terminals that move at random transmit data to all other communication terminals within the communication range of the own communication terminal. The other is a message ferry method in which a mobile communication terminal that circulates between fixed communication terminals exchanges data with the fixed communication terminal. As yet another method, in the routing protocol part of each communication terminal, the distribution probability to the destination communication terminal is calculated based on the history of the end-to-end route from the past to the present to the destination communication terminal in the routing table, There is a method of determining the next hop node when the communication terminal transfers the transfer data based on the distribution probability to the destination communication terminal calculated by each of these communication terminals (see, for example, Patent Document 1).

Furthermore, it has been proposed that a plurality of communication terminals exchange each other's information and synchronize possessed information using the epidemic method (see Non-Patent Document 2, for example). More specifically, when a communication terminal detects another communication terminal, it exchanges a holding list (also called a summary vector) that is a list of data (content) held by itself, and the contents of the holding list of the other communication terminal To figure out. And a communication terminal investigates the data which the own terminal does not hold | maintain based on the received holding list, and tries to acquire the data by exchanging a communication message with other communication terminals.

Moreover, there are Patent Document 2 and Patent Document 3 as other documents describing a communication method between communication terminals. In the technique described in Patent Document 2, the transmission side terminal generates signature data for each unit data composed of communication data for M times, and N (N is an integer satisfying M ≧ N ≧ 2). ) The divided divided signature data is added to the communication data and divided and transmitted. On the other hand, the receiving side terminal reconstructs the unit data from the received communication data, and reconstructs the signature data from the divided signature data added to the received communication data. The validity of the received communication data is verified for each reconfigured unit data using the reconstructed signature data.

In the technique described in Patent Document 3, the position and relative speed of the counterpart terminal is detected before a communication terminal mounted on a vehicle starts communication with a communication terminal mounted on another vehicle by short-range wireless communication. Then, the communication possible time is estimated, and the communication protocol to be used is selected according to the estimation result. Specifically, when the communicable time is long, a general communication protocol is selected. When the communicable time is short, a light communication protocol is selected so that data can be exchanged even if it is short.

WO2009 / 0778427 JP 2011-229075 A JP 2005-348262 A

In ITS (Intelligent Transport Systems), examination of vehicle-to-vehicle communication for exchanging information between vehicles using radio is underway. As one of the scenes, as shown in FIG. 19 (a), considering that data is transmitted and received between oncoming vehicles, depending on the moving speed of each other, sufficient communication to transmit and receive the data It is assumed that time cannot be secured, and as a result, as shown in FIG. 19B, transmission / reception of large data fails. That is, when data is transmitted from the vehicle B1 toward the vehicle A1 traveling in the opposite lane, if the relative speed between the vehicle A1 and the vehicle B1 is large, sufficient communication time cannot be secured. Sending / receiving fails.

Even if DTN is applied to the above-mentioned inter-vehicle communication, data is divided into a plurality of bundles in the vehicle B1, and each bundle is transmitted to the vehicle A1, the communication time is still limited so that the vehicle A1 can receive it. Limited to part bundles. Therefore, when the vehicle B1 detects that the ACK for the transmitted bundle has not been transmitted from the vehicle A1 due to a timeout, the vehicle B1 waits for transfer while accumulating the remaining bundles, and performs data transfer when connected to the next hop. become. However, since the vehicle A1 is no longer away from the vehicle B1 at that time, the probability that the vehicle A1 exists in the communicable area of the next hop destination vehicle of the vehicle B1 is very small. Therefore, even if the remaining bundle is transmitted to the next hop destination vehicle, the bundle cannot be transmitted from the next hop destination vehicle to the vehicle A1, and the transfer is waited while the bundle is accumulated even at the next hop destination. Become. As a result, a considerably long time is required until all bundles reach the destination vehicle A1.

An object of the present invention is to quickly deliver data to a destination communication terminal in the above-described problem, that is, in the method of waiting for transfer of the remaining bundle and transmitting to the next hop destination in response to failure of the bundle transmitted to the destination. This is to provide a communication system that solves the problem that it is difficult.

A communication system according to a first aspect of the present invention includes:
A communication system having a receiving terminal, a plurality of transmitting terminals constituting a formation, and a management terminal,
The management terminal
A communication unit that performs wireless communication;
A data storage unit for storing data;
A formation information storage unit for storing formation information that is information on the formation;
A data division arrangement determination unit for determining a data division method and a distributed arrangement method based on the formation information;
The data is divided into a plurality of partial data according to the determined division method, the partial data obtained by the division, transmission destination information in which the receiving terminal is set as a transmission destination, the partial data and the division source A data division arrangement unit that transmits a bundle having relationship information with the data to the plurality of transmission terminals of the distributed arrangement destination determined by the determined distributed arrangement method through the communication unit of the own terminal;
Each of the transmitting terminals
A communication unit that performs wireless communication;
A bundle storage unit;
A bundle receiving unit that stores the bundle received by the communication unit of the terminal from the management terminal in the bundle storage unit of the terminal;
When the bundle having the transmission destination information with the reception terminal set as the transmission destination is input from the bundle storage unit and the reception terminal detects that the reception terminal is within the communicable range of the own terminal, the bundle is A bundle transmission unit that transmits to the receiving terminal through the communication unit of the terminal,
The receiving terminal
A communication unit that performs wireless communication;
A data storage unit;
A bundle storage unit;
A bundle reception unit that stores the bundle received by the communication unit of the terminal from a plurality of the transmission terminals in the bundle storage unit;
The bundle having the transmission destination information set as the transmission destination is input from the bundle storage unit of the local terminal, and based on the relation information between the partial data in the bundle and the data of the division source, A data reconfiguration unit that combines the partial data in the bundle to reconfigure the division source data and stores it in the data storage unit of the terminal itself.

A communication method according to the second aspect of the present invention includes:
A communication method executed by a communication system having a receiving terminal, a plurality of transmitting terminals constituting a formation, and a management terminal,
Based on the information related to the platoon, the management terminal determines a data division method and a distributed arrangement method to be transmitted to the receiving terminal,
The management terminal divides the data into a plurality of partial data according to the determined division method, the partial data obtained by the division, transmission destination information in which the reception terminal is set as a transmission destination, and the partial A bundle having data and relation information between the data of the division source is transmitted by radio communication to the plurality of transmission terminals of the distributed arrangement destination determined by the determined distributed arrangement method,
Each of the transmitting terminals stores the bundle received from the management terminal, and transmits the bundle to the receiving terminal by wireless communication when detecting that the receiving terminal has entered the communicable range of the own terminal. And
The receiving terminal combines the partial data in the plurality of bundles based on the relationship information between the partial data in the bundle received from the plurality of transmitting terminals and the original data of the division source. Reconstruct the data.

A communication terminal according to the third aspect of the present invention is:
A communication unit that performs wireless communication;
A data storage unit for storing data to be transmitted to the receiving terminal;
A formation information storage unit for storing formation information that is information relating to the formation composed of a plurality of transmission terminals;
A data division arrangement determination unit for determining a data division method and a distributed arrangement method based on the formation information;
The data is divided into a plurality of partial data according to the determined division method, the partial data obtained by the division, transmission destination information in which the receiving terminal is set as a transmission destination, the partial data and the division source A data division arrangement unit that transmits the bundle having the relationship information with the data to the plurality of transmission terminals that are the distributed arrangement destinations determined by the determined distributed arrangement method, through the communication unit.

Since the present invention has the above-described configuration, data can be quickly delivered to the destination communication terminal.

1 is a configuration diagram of a communication system according to a first embodiment of the present invention. It is a block diagram of the management terminal in the 1st Embodiment of this invention. It is a block diagram of the transmission terminal in the 1st Embodiment of this invention. It is a block diagram of the receiving terminal in the 1st Embodiment of this invention. It is a flowchart which shows the operation example of the management terminal in the 1st Embodiment of this invention. It is a flowchart which shows the operation example of the transmission terminal in the 1st Embodiment of this invention. It is a flowchart which shows the operation example of the receiving terminal in the 1st Embodiment of this invention. It is a schematic diagram which shows a mode that the transmission data which a management terminal holds in the 1st Embodiment of this invention are divided | segmented and transmitted to the receiving terminal from the several transmitting terminal which comprises a formation, and are reconfigure | reconstructed by the receiving terminal side . It is a block diagram of the communication terminal which concerns on the 1st Embodiment of this invention. It is a block diagram of the communication terminal which concerns on the 2nd Embodiment of this invention. It is a schematic diagram which shows an example of the division | segmentation method and the distribution method of the transmission object data in the 2nd Embodiment of this invention. It is a flowchart which shows an example of the division | segmentation method and the distribution method of the transmission object data in the 2nd Embodiment of this invention. It is a schematic diagram which shows another example of the division | segmentation method and the distribution method of the transmission object data in the 2nd Embodiment of this invention. It is a flowchart which shows another example of the division | segmentation method of the transmission object data in the 2nd Embodiment of this invention, and the distribution method. It is a figure which shows another example of the division | segmentation method and the distribution method of the transmission object data in the 2nd Embodiment of this invention. It is a schematic diagram which shows another example of the division | segmentation method and the distribution method of the transmission object data in the 2nd Embodiment of this invention. It is a flowchart which shows another example of the division | segmentation method and the distribution method of the transmission object data in the 2nd Embodiment of this invention. It is a figure which shows the other example of the division | segmentation method and the distribution method of the transmission object data in the 2nd Embodiment of this invention. It is a schematic diagram for demonstrating the subject of vehicle-to-vehicle communication. It is a block diagram of the communication terminal which concerns on the 3rd Embodiment of this invention.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
[First embodiment]
Referring to FIG. 1, the communication system 100 according to the first embodiment of the present invention includes a reception terminal 110, a plurality of transmission terminals 120, and a management terminal 130. Here, the management terminal 130 is a wireless communication terminal serving as a data transmission start point, the plurality of transmission terminals 120 are wireless communication terminals serving as data transmission relay points, and the reception terminal 110 is a wireless communication terminal serving as an end point of data transmission. Further, the plurality of transmission terminals 120 constitute a platoon. Further, the receiving terminal 110 is moving from the left to the right of the page, and the transmitting terminal 120 and the management terminal 130 are moving in a row from the right to the left of the page. Such a situation typically appears, for example, in a scene in which a vehicle in which the receiving terminal 110 is mounted and a vehicle group that forms a platoon in which the transmitting terminal 120 and the management terminal 130 are mounted travel in opposite lanes. However, the present invention is not limited to vehicle-to-vehicle communication, and can also be applied to communication between persons who have portable communication terminals.

2, the management terminal 130 includes a communication unit 131, a data storage unit 132, a formation information storage unit 133, a data division arrangement determination unit 134, and a data division arrangement unit 135.

The communication unit 131 has a function of transmitting and receiving data to and from other communication terminals wirelessly. The communication unit 131 controls communication protocols in the transport layer and lower layers. In this embodiment, TCP is used for the transport layer. However, the present invention is not limited to TCP, and other communication protocols such as UDP may be used. The communication protocol below the link layer is arbitrary as long as wireless communication is possible.

The data storage unit 132 has a function of storing data to be transmitted to the receiving terminal 110. The type of data is arbitrary. For example, any of text data, image data, and audio data may be used, or they may be mixed. The data may be called content. The data storage unit 132 is composed of, for example, a hard disk.

The formation information storage unit 133 stores information related to formations (hereinafter referred to as formation information) by the plurality of transmission terminals 120. The formation information includes at least information (for example, a communication address) that identifies each transmission terminal 120 constituting the formation. Other information may be included. For example, position information (for example, longitude and latitude, or a distance from a specific terminal serving as a reference to the transmission terminal) in the formation may be included in the formation information. Moreover, the communication speed of each transmitting terminal may be included in the formation information. Further, information on the moving speed of each transmitting terminal may be included in the formation information. Of the formation information, static information such as a communication address may be set once in advance if there is no change in the members constituting the formation. Dynamic information such as position information of each transmission terminal in the formation information may be obtained by periodically communicating with each transmission terminal 120 through the communication unit 131 and stored in the formation information storage unit 133.

The data division arrangement determining unit 134 inputs the column information from the column information storage unit 133, and divides the data to be transmitted to the receiving terminal 110 and a plurality of partial data obtained by dividing the data by the division method into a plurality of partial data. It has a function of determining a method of distributing and arranging the transmission terminals 120. For example, the data division arrangement determining unit 134 recognizes the total number N of the transmission terminals 120 constituting the platoon from the number of communication addresses in the platoon information, etc., divides the data into N, and separates the partial data from the respective transmission terminals 120. Decide to place in. Or the data division arrangement | positioning determination part 134 recognizes the total number N of the transmission terminals 120 which comprise a formation from the formation information, and the position of each transmission terminal 120, and the some transmission terminal 120 which distance is close to below a threshold value Are grouped into one group, and the total number of groups is M, the data is divided into M, and it is determined that each partial data is allocated to all the transmission terminals 120 or some of the transmission terminals 120 of different groups. Alternatively, the data division arrangement determining unit 134 recognizes the communication speed, the moving speed, and the like of each transmission terminal 120 constituting the formation from the formation information as an index value of the transmission terminal, and selects each transmission terminal 120 as a relay point. Is calculated based on the index value of the transmitting terminal, the transmitting terminal 120 whose score is better than the threshold value or the transmitting terminal 120 having the highest nth score is determined, and the data is determined as described above It divides by the number of transmission terminals that have been determined, and decides to arrange the individual partial data in the respective transmission terminals 120 determined as described above.

The data division arrangement unit 135 inputs data from the data storage unit 132, inputs the division method and distributed arrangement method determined from the data division arrangement determination unit 134, and converts the data into a plurality of partial data according to the input division method. There is a function of dividing and transmitting individual partial data obtained by the division as a bundle to a plurality of transmission terminals 120 through the communication unit 131 according to the distributed arrangement method. The transmitted bundle is composed of partial data and a header. The header includes transmission destination information in which the communication address of the receiving terminal 110 is set as a transmission destination of partial data, and relationship information between the partial data and the division source data. The relationship information includes a data identifier that uniquely identifies the original data, a partial data identifier that uniquely identifies the partial data, and position information (such as a byte position) in the original data of the partial data.

In the present embodiment, it is assumed that all the transmission terminals 120 in which the partial data are arranged exist in the communicable area of the management terminal 130. However, the management is performed because the formation is long or the like. When there is a transmitting terminal 120 that is outside the communicable area of the terminal 130, the management terminal 130 performs communication by changing the position in the formation, or the communication is performed via the transmitting terminal 120 existing in the communicable area. Is called.

3, the transmission terminal 120 includes a communication unit 121, a bundle storage unit 122, a bundle reception unit 123, and a bundle transmission unit 124.

The communication unit 121 has the same function as the communication unit 131 of the management terminal 130.

The bundle storage unit 122 has a function of storing a bundle. The bundle storage unit 122 is composed of, for example, a hard disk.

The bundle reception unit 123 and the bundle transmission unit 124 control the communication protocol of the bundle layer higher than the transport layer. Among these, the bundle receiving unit 123 has a function of receiving a bundle from the management terminal 130 through the communication unit 121 and storing the bundle in the bundle storage unit 122. On the other hand, when the bundle transmission unit 124 inputs a bundle having transmission destination information with the reception terminal 110 set as a transmission destination from the bundle storage unit 122 and detects that the reception terminal 110 has entered the communicable range of its own terminal, A function of transmitting the bundle to the receiving terminal 110 through the communication unit 121 is provided. In the detection, for example, when the receiving terminal 110 broadcasts information including the communication address of its own terminal to the surroundings in the detection, the bundle transmission unit 124 receives the received communication address and the transmission destination information in the bundle. The receiving terminal 110 is detected by collating with the communication address of the receiving terminal 110 represented by Note that the bundle transmission unit 124 may divide the bundle input from the bundle storage unit 122 into a plurality of smaller bundles and transmit the bundle to the reception terminal 110.

4, the receiving terminal 110 includes a communication unit 111, a bundle storage unit 112, a data storage unit 113, a bundle reception unit 114, and a data reconstruction unit 115.

The communication unit 111 has the same function as the communication unit 131 of the management terminal 130. The bundle storage unit 112 has the same function as the bundle storage unit 122 of the transmission terminal 120. The data storage unit 113 has the same function as the data storage unit 132 of the management terminal 130. The bundle reception unit 114 has the same function as the bundle reception unit 123 of the transmission terminal 120.

The data reconfiguration unit 115 inputs all bundles having transmission destination information with the terminal 110 set as the transmission destination from the bundle storage unit 112, and based on the relationship information between the partial data in each bundle and the division source data Thus, it has a function of reconstructing the original data by combining adjacent partial data in the same original data. The data reconstruction unit 115 has a function of storing the reconstructed data in the data storage unit 113.

Next, the operation of the communication system according to the present embodiment will be described with reference to the flowcharts of FIGS.

First, the operation of the management terminal 130 will be described with reference to FIG.

The management terminal 130 starts the process shown in FIG. 5 when a transmission instruction specifying the identifier of the data to be transmitted and the identifier (for example, communication address) of the receiving terminal 110 as the transmission destination is given from the user or the like. First, the data division arrangement determination unit 134 of the management terminal 130 inputs the formation information of the transmission terminal 120 from the formation information storage unit 133, and determines the data division method and the distribution arrangement method to be transmitted based on the formation information. Determine (step S101).

Next, the data division arrangement unit 135 of the management terminal 130 inputs data to be transmitted from the data storage unit 132, and divides the data according to the division method determined by the data division arrangement determination unit 134 (step S102). Next, the data division arrangement unit 135 generates a bundle by adding a header to each partial data obtained by division, and the generated bundle is determined by the distributed arrangement method determined by the data division arrangement determination unit 134. The data is transmitted to the destination transmission terminal 120 (step S103). The processing in step S103 needs to be completed before the sending terminal 120 forming the formation encounters the receiving terminal 110.

Next, the operation of the transmission terminal 120 will be described with reference to FIG.

When the bundle reception unit 123 of each transmission terminal 120 receives a bundle from the management terminal 130 through the communication unit 121, the bundle reception unit 123 stores the bundle in the bundle storage unit 122 (step S111).

Next, the bundle transmission unit 124 of each transmission terminal 120 inputs a bundle from the bundle storage unit 122, and whether or not the reception terminal 110 specified by the transmission destination information in the bundle has entered the communicable range of the own terminal. Is detected (step S112). When detecting that the receiving terminal 110 has entered the communicable range, the bundle transmitting unit 124 transmits the bundle to the receiving terminal 110 through the communication unit 121 (step S113).

Next, the operation of the receiving terminal 110 will be described with reference to FIG.

When the bundle reception unit 114 of the reception terminal 110 receives a bundle from any of the transmission terminals 120 through the communication unit 111, the bundle reception unit 114 stores the bundle in the bundle storage unit 112 (step S131). The bundle receiving unit 114 repeats the operation of receiving and storing the bundle until all bundles constituting the original data are received (step S132).

When the reception and storage of all the bundles are completed, the data reconfiguration unit 115 inputs all the bundles having the transmission destination information in which the own terminal 110 is set as the transmission destination from the bundle storage unit 112, and the partial data in each bundle Based on the relationship information with the division source data, adjacent partial data in the same original data are combined to reconstruct the division source data (step S133). Then, the data reconstruction unit 115 stores the reconstructed data in the data storage unit 113 (step S134).

FIG. 8 is a schematic diagram illustrating a state in which transmission data held by the management terminal 130 is divided and transmitted from a plurality of transmission terminals 120 constituting a formation to the reception terminal 110, and the original data is reconstructed on the reception terminal 110 side. It is. As shown in FIG. 8A, the vehicle A1 equipped with the receiving terminal 110 is traveling in one lane, and the vehicles B1 to B3 equipped with the transmitting terminal 120 are traveling in the opposite lane. The management terminal 130 divides the data to be transmitted to the receiving terminal 110 into three, and distributes each transmission data to the vehicles B1 to B3.

Thereafter, when the distance between the vehicle B1 to B3 and the vehicle A1 approaches and the vehicle A1 enters the communicable range of the vehicle B1, the first transmission data is transmitted from the transmission terminal 120 of the vehicle B1 toward the vehicle A1. And received by the receiving terminal 110 of the vehicle A1. Subsequently, when the vehicle A1 enters the communicable range of the vehicle B2, the next transmission data is transmitted from the transmission terminal 120 of the vehicle B2, and is received by the reception terminal 110 of the vehicle A1. Further, when the vehicle A1 enters the communicable range of the vehicle B3, the last transmission data is transmitted from the transmission terminal 120 of the vehicle B3 and received by the reception terminal 110 of the vehicle A1. As shown in FIG. 8B, the receiving terminal 110 combines these received transmission data to reconstruct the data.

Thus, according to the present embodiment, the data held by the management terminal 130 can be quickly delivered to the receiving terminal 110. The reason is that the data to be transmitted to the destination receiving terminal is divided into a plurality of partial data and distributed in advance to the plurality of transmitting terminals 120 constituting the platoon, and the plurality of transmitting terminals 120 can communicate with each other. This is because, when it is detected that the receiving terminal 110 has entered the range, the partial data arranged in itself is transmitted to the receiving terminal 110.

In the present embodiment, there has been described a case where there are three types of communication terminals that constitute the communication system 100: a management terminal, a transmission terminal, and a reception terminal. However, each communication terminal has a plurality of types other than dedicated types. You may have a function. That is, the communication terminals constituting the communication system 100 have any one, any two, or all three of the functions of the management terminal, the function of the transmitting terminal, and the function of the receiving terminal. It may be. FIG. 9 shows a configuration example of a communication terminal having the function of the management terminal 130, the function of the transmission terminal 120, and the function of the reception terminal 110.

9, the communication terminal 140 includes a communication unit 141, a data storage unit 142, a formation information storage unit 143, a data division arrangement determination unit 144, a data division arrangement unit 145, a bundle storage unit 146, a bundle reception unit 147, and a bundle. A transmission unit 148 and a data reconstruction unit 149 are included.

The communication unit 141, the data storage unit 142, the formation information storage unit 143, the data division arrangement determination unit 144, and the data division arrangement unit 145 are the communication unit 131, the data storage unit 132, the formation information storage unit 133, and the data division of the management terminal 130. It has the same function as the arrangement determination unit 134 and the data division arrangement unit 135. The bundle storage unit 146 has the functions of the bundle storage unit 122 of the transmission terminal 120 and the bundle storage unit 112 of the reception terminal 110. The bundle reception unit 147 has the functions of the bundle reception unit 123 of the transmission terminal 120 and the bundle reception unit 114 of the reception terminal 110. The bundle transmission unit 148 has the same function as the bundle transmission unit 124 of the transmission terminal 120. The data reconstruction unit 149 has the same function as the data reconstruction unit 115 of the receiving terminal 110.

When the communication terminal 140 operates as the management terminal 130 and the transmission terminal 120, the communication terminal 140 transmits a bundle to be allocated from the data division arrangement unit 145 to the own terminal as the transmission terminal with the communication unit 141 and the bundle reception unit 147. Or the bundle storage unit 146 is accessed and stored from the data division arrangement unit 145 as indicated by the broken line in FIG.

In this embodiment, since the transmission terminal 120 transmits a bundle when the reception terminal 110 is detected, the bundle is held in the transmission terminal 120 when the reception terminal 110 cannot be detected. Will remain. In order to prevent this, the transmission terminal 120 transmits the bundle to any other communication terminal when the reception terminal 110 is not detected after a certain period of time has elapsed after receiving the bundle from the management terminal 130. You may do it. The bundle transmitted in this way takes some time, but is delivered to the receiving terminal 110 by the DTN function.

[Second Embodiment]
In this embodiment, another example of a communication terminal that functions as a management terminal will be described. Referring to FIG. 10, the communication terminal 11 according to the second embodiment of the present invention includes a data receiving unit 12, a data storage unit 13, a formation information storage unit 14, a list creation unit 15, and a bundle generation / distribution destination calculation unit 16. And a bundle transmission unit 17.

The data receiving unit 12 has a function of receiving information on the formation from other vehicles. Here, the information on the platoon is the number of vehicles constituting the platoon, the position information thereof, and the like. The data storage unit 13 has a function of storing arbitrary data to be transmitted. The formation information storage unit 14 has a function of storing and holding information on formations received by the data reception unit 12. The list creation unit 15 has a function of creating a list of the data stored in the data storage unit 13 and the formation information stored in the formation information storage unit 14. The bundle generation / distribution destination calculation unit 16 has a function of determining the number of divided bundles and the arrangement pattern of the divided bundles for each data with reference to the list. The bundle transmission unit 17 has a function of transmitting a bundle corresponding to each vehicle by unicast according to the above determination.

Next, the operation of the communication terminal 11 according to this embodiment will be described.

First, as shown in FIG. 11, a description will be given of a case where the number of data to be transmitted is determined from the number of vehicles constituting the same platoon and arranged equally in each vehicle. In this case, information on the number of vehicles belonging to the same platoon is shared in advance in the platoon. When data to be transmitted to the oncoming vehicle is generated in the communication terminal 11, the communication terminal 11 functions as a management terminal and a transmission terminal, and is based on the information on the number of vehicles in the row to which the communication terminal 11 belongs. Is broken into evenly sized bundles. Then, the corresponding bundle is transmitted to other vehicles by unicast, and the bundle is arranged in the formation. Here, the transmission destination of the bundle may be not only a vehicle but also a data collection or communication device on the road represented by an ITS spot.

FIG. 12 shows a flowchart of a method in which the communication terminal 11 determines the number of divisions of data to be transmitted from the number of vehicles constituting the same platoon, generates a bundle, and arranges it evenly on each vehicle. . When a data transmission request is generated on the communication terminal 11, the communication terminal 11 executes processing for dividing and arranging data into bundles shown in FIG.

In the process of step S21 in FIG. 12, information on the number of vehicles in the platoon to which the communication terminal 11 belongs is obtained. Next, in the process of step S22, the communication terminal 11 divides the data to be transmitted into bundles based on the information on the number of vehicles in the row to which the communication terminal 11 belongs, and calculates which bundle is arranged for each vehicle. In the case of this example, since the number of divisions is determined only by the number of vehicles, the bundle is calculated so as to be evenly arranged on each vehicle. In the process of step S23, the communication terminal 11 arranges the bundle in the platoon by transmitting an appropriate bundle by unicast to other vehicles in the platoon to which the communication terminal 11 belongs based on the process result of step S22.

After the process in FIG. 12 is completed, the vehicle in which the bundle is arranged may transmit the bundle when the destination vehicle is found. Thereby, the destination vehicle can receive the bundle one after another from the vehicle in which the bundle is arranged, and can restore and receive the original transmission data by assembling the received bundle.

There are several possible methods for the process in step S21 in FIG. For example, by forming a formation in advance and periodically exchanging information on the number of vehicles in the formation, when a data transmission request occurs on the communication terminal 11, a method of reading from the storage unit of the own terminal, A method of inquiring and obtaining the latest information at the time of the request from other vehicles in the platoon is conceivable. As for the method of transmitting the information on the number of vehicles, the vehicles belonging to the same platoon may be exchanged using unicast delivery, or may be shared by broadcast delivery using flooding or epidemic methods.

Next, as shown in FIG. 13, the division number of the transmission target data is determined from the number of vehicles constituting the same platoon and the position information of each vehicle, and the bundle arrangement calculation is performed. The operation | movement arrange | positioned to is demonstrated. In this case, information on the number of vehicles belonging to the same platoon and position information of each vehicle belonging to the platoon are shared in advance in the platoon. In the communication terminal 11, when data to be transmitted to the oncoming vehicle is generated, the communication terminal 11 functions as a management terminal and a transmission terminal, and is based on information on the number of vehicles and positions of the platoon to which the communication terminal 11 belongs. Is divided into bundles of an appropriate size, and placement calculation is performed. As an example, as shown in FIG. 13A, a method may be used in which the distance between the vehicles traveling in the platoon is short only on one vehicle and the bundle is not placed on the other. Alternatively, as shown in FIG. 13B, a method of arranging duplicates in preparation for missing may be used. Then, the corresponding bundle is transmitted to other vehicles by unicast, and the bundle is arranged in the formation. Here, the transmission destination of the bundle may be not only a vehicle but also a data collection or communication device on the road represented by an ITS spot.

FIG. 14 shows a flowchart of an implementation method in which the communication terminal 11 determines the number of divisions of data to be transmitted from the number of vehicles constituting the same platoon and the position information of each vehicle and arranges the data in each vehicle. Yes. When a data transmission request is generated on the communication terminal 11, the communication terminal 11 executes processing for dividing and arranging data into bundles as shown in FIG. Here, steps S21 and S23 are the same as in FIG.

In the process of step S24 after the process of step S21, the communication terminal 11 acquires the position information of each vehicle in the platoon to which it belongs. In the process of the next step S25, the communication terminal 11 divides the data to be transmitted into bundles based on the number of vehicles and position information of the platoon to which it belongs, and calculates which bundle is arranged for each vehicle. For example, first, the data to be transmitted is divided by the number of vehicles, but the distance between other vehicles in the formation is less than a certain value (eg, 2 m) when the bundle size is small. Because it is possible that the transmission of the bundle can be completed with only one unit of communication, or the communication band may be compressed by arranging the bundles on two units. It can be considered that the calculation is performed so that the bundle is not arranged on one of the vehicles. And a bundle is arrange | positioned by the process of step S23.

Bundled reception method has already been explained and will be omitted.

There are several possible methods for the processing in step S24. For example, as a means for the terminals belonging to the platoon to acquire the respective position information, a method of receiving GPS or quasi-zenith satellite data or a method of receiving from the oncoming vehicle receiving the above-described data can be considered. In addition, as a method for acquiring all the vehicle information belonging to the platoon, the position information of each vehicle is periodically exchanged in the platoon, and a data transmission request is generated on the communication terminal 11 A method of reading from the storage unit of the own terminal at the time, or a method of inquiring and acquiring the latest information at the time of request generation from other vehicles in the platoon. Further, the position information transmission method for each vehicle may be exchanged between vehicles belonging to the same platoon using unicast distribution, or shared by broadcast distribution using flooding or epidemic methods.

In addition, there are several methods for the process of step S25. For example, in association with the acquired position information of each vehicle, the communication speed of each vehicle belonging to the platoon is newly acquired, the transmission target data is divided into bundles according to the ratio of the communication speed of each vehicle, and A method of arranging can be considered. A specific example is shown in FIG.

In the example shown in FIG. 15, the case where the communication terminal 11 transmits 300 MB of data is considered. The communication terminal 11 first obtains the total communication speed of the vehicles B1 to B5 belonging to the platoon. For example, when the communication speeds of the vehicles B1 to B5 are the values shown in FIG. 15, the total communication speed is 250 Mbps. Next, in order to determine the bundle size and the arrangement vehicle, the communication speed and the total ratio of the vehicles B1 to B5 in the platoon are calculated. For example, in the case of the vehicle B1, the communication speed is 60 Mbps, so 60/250 = 0.24. Finally, based on this, the size of the bundle to be arranged in each of the vehicles B1 to B5 is determined. For example, in the case of the vehicle B1, 300 × 0.24 = 72 MB.

Further, the distance that can be directly communicated from the communication terminal 11 is calculated from the position information of each of the vehicles B1 to B5, and based on the calculated distance, the vehicle that is within the communicable distance is out of the distance (communication is impossible without hopping). A method of changing the distribution of the bundle size between vehicles existing in the vehicle is also conceivable. In addition, the distance between adjacent vehicles B1 to B5 is calculated from the position information of each vehicle B1 to B5, and vehicles that are separated by a certain distance (eg, 10 m) or less than a certain threshold value (eg, 1 Mbps). For the vehicle, a method of removing the bundle from the arrangement target even in the same platoon and rearranging the bundle again can be considered. In this case, in addition to the inter-vehicle distance and the communication speed, the condition to be excluded from the bundle arrangement target may include the size of data to be transmitted, the bundle size scheduled to be arranged, and the like.

Next, as shown in FIG. 16, from the number of vehicles constituting the same platoon, the position information of the vehicles, and the feature information of the running road, the method of dividing and distributing the data to be transmitted A method for determining the above will be described. Here, the road feature information means, for example, information indicating whether the vehicle is traveling on an intricate road such as a general road, or whether the vehicle is traveling on a substantially single road such as an expressway. The feature information of the running road can be determined, for example, by acquiring information on the currently running road from a car navigation system mounted on the vehicle.

As shown in FIG. 16 (a), when a platoon travels on a general road, the platoon travel cannot be maintained for a long time on the general road, and the vehicles constituting the platoon frequently change or travel at a low speed. As a result, the communicable time with the oncoming vehicle is expected to be long, so the bundle size is set to be large and arranged in a small number of vehicles. On the other hand, as shown in FIG. 16B, when a platoon is traveling on a highway, the platooning can be maintained for a long time on the highway, and the vehicles constituting the platoon are less likely to be replaced compared to a general road. In addition, since it is expected that the communicable time with the oncoming vehicle is short due to traveling at high speed, the bundle size is set small and arranged in a large number of vehicles. Here, the transmission destination of the bundle may be not only a vehicle but also a data collection or communication device on the road represented by an ITS spot.

In FIG. 17, the communication terminal 11 determines the number of divisions of transmission target data using the number of vehicles constituting the same platoon, the position information of each vehicle, and the road feature information, and arranges the data in each vehicle. 2 shows a flowchart of an implementation method. When a data transmission request is generated on the communication terminal 11, the communication terminal 11 executes processing for dividing and arranging data into bundles as shown in FIG. Here, steps S21, S23, and S24 are the same as those in FIG.

In the process of step S26 after the processes of steps S21 and S24, the communication terminal 11 acquires the road feature information of the platoon to which it belongs. Here, the road feature information is information indicating whether the vehicle is traveling on an intricate road such as a general road, or whether the vehicle is traveling on a substantially single road such as an expressway. In the process of step S27, the communication terminal 11 divides the transmission target data into bundles based on the number of vehicles in the row to which the communication terminal 11 belongs, the position information, and the road feature information, and determines which bundle is arranged for each vehicle. calculate. For example, if a convoy is traveling on a general road, it is difficult to maintain the convoy with the same vehicle group, so the location information of each vehicle's destination is shared within the convoy and the distance between destinations is A method may be considered in which vehicles that are far apart are not included in the bundle arrangement calculation. In addition, when driving on an expressway, the same formation is considered to be maintained for a long time. Even if it is, the method of including in bundle arrangement | positioning calculation etc. can be considered.

Bundled reception method has already been explained and will be omitted.

Furthermore, as another example of the transmission target data division and the distributed arrangement method, an index for determining the number of transmission target data divisions (the number of vehicles running in a platoon, position information of vehicles in the platoon, There is a method of using road features on which a convoy is traveling alone or in combination.

In addition, as shown in FIG. 18, an arbitrary weight is assigned to each index, and all vehicles whose evaluation value by an arbitrary evaluation function is equal to or higher than a threshold value or a certain number of vehicles having a higher evaluation value are bundled. You may determine as an object of arrangement. In the example of FIG. 18, four types of an inter-vehicle distance x, a communication speed y, a movement speed v, and a communication arrival rate p with an adjacent vehicle are used as indices. Here, the communication arrival rate p is a communication arrival rate according to the bundle arrangement, and the higher the vehicle (B2 or the like) whose distance from the transmission source vehicle B3 (the vehicle on which the communication terminal 11 is mounted) is shorter. Value. As an evaluation function for obtaining an evaluation value, for example, the following equation can be used. The evaluation function may always use the same function, or the evaluation function used for road feature information may be changed.
h (x, y, v, p) = - (k x x + k y y + k v v + k p p) ... (1)
However, k _x , k _y , k _v , and k _p are weights in each index. The weight given to the index may be given by the user as a fixed value, or a corresponding weight may be given from road feature information or the like. For example, if each of the vehicles B1 to B6 has an index value as shown in FIG. 18B and the weights are k _x = 0.01, k _y = 0.1, k _v = 0.01, k _p = 0.1, the vehicle B3 The evaluation function value (= evaluation value h) of each vehicle except for is the value shown in FIG. As a result, for example, the transmission target data on the transmission source vehicle B3 (the vehicle on which the communication terminal 11 is mounted) is divided into four, and the data is distributed to the top three units that minimize the evaluation function other than itself. In this case, the result of whether or not the bundle can be arranged is as shown in FIG.

Furthermore, it is also possible to place bundles on the assumption that roadside radios temporarily belong to the line. Thereby, it is considered that the transmission terminal serving as a relay point is not limited to the communication terminal mounted on the vehicle, but can be implemented in communication between the mobile unit and the terminal.

Also, if the transmission data size is relatively large compared to the communication speed of the communication terminal 11, the transmission speed of the current terminal, the number of vehicles belonging to the same platoon, Since it is difficult to completely transmit the target data, for example, a method of notifying the oncoming vehicle of reception difficulty and attempting to acquire from another means such as via a mobile phone network such as 3G or from other platooning vehicles A method in which the oncoming vehicle on the receiving side forms a platoon with other oncoming vehicles and receives them in cooperation, a method of trying to compress data to be transmitted, and the like can be considered.

As described above, according to the present embodiment, even if the size of the data cannot be reliably transmitted to the oncoming vehicle by one unit, the original file is bundled into an appropriate size bundle to other vehicles belonging to the platoon. By dividing and arranging and transmitting to the oncoming vehicle in units of platoons, it becomes possible to reliably receive the data transmitted by the oncoming vehicle.

[Third embodiment]
FIG. 20 shows an example of a hardware configuration when the communication terminal in each of the above-described embodiments is configured by an electronic information processing apparatus such as a computer. The communication terminal 910 in this example includes a CPU (Central Processing Unit) peripheral part, an input / output part, and a legacy input / output part. The CPU peripheral section includes a CPU 902, a RAM (Random Access Memory) 903, a graphic controller 904, and a display device 905 that are connected to each other by a host controller 901. The input / output unit includes a communication interface 907, a hard disk drive 908, and a CD-ROM (Compact Disk Read Only Memory) drive 909 connected to the host controller 901 by the input / output controller 906. The legacy input / output unit includes a read only memory (ROM) 910, a flexible disk drive 911, and an input / output chip 912 that are connected to the input / output controller 906.

The host controller 901 connects the RAM 903, the CPU 902 that accesses the RAM 903 at a high transfer rate, and the graphic controller 904. The CPU 902 operates based on programs stored in the ROM 910 and the RAM 903 to control each unit. The graphic controller 904 acquires image data generated by the CPU 902 or the like on a frame buffer provided in the RAM 903 and displays the image data on the display device 905. Instead of this, the graphic controller 904 may include a frame buffer for storing image data generated by the CPU 902 or the like.

The input / output controller 906 connects the host controller 901 to the hard disk drive 908, the communication interface 907, and the CD-ROM drive 909, which are relatively high-speed input / output devices. The hard disk drive 908 stores programs and data used by the CPU 902. The communication interface 907 transmits / receives a program or data by connecting to another communication terminal. The CD-ROM drive 909 reads a program or data from the CD-ROM 992 and provides it to the hard disk drive 908 and the communication interface 907 via the RAM 903.

The input / output controller 906 is connected to a ROM 910, a flexible disk drive 911, and a relatively low-speed input / output device such as an input / output chip 912. The ROM 910 stores a boot program that is executed when the communication terminal 910 is started up, a program that depends on the hardware of the communication terminal 910, and the like. The flexible disk drive 911 reads a program or data from the flexible disk 993 and provides it to the hard disk drive 908 and the communication interface 907 via the RAM 903. The input / output chip 912 connects various input / output devices via the flexible disk drive 911 or a parallel port, a serial port, a keyboard port, a mouse port, and the like.

The program executed by the CPU 902 is stored in a recording medium such as the flexible disk 993, the CD-ROM 992, or an IC (Integrated Circuit) card and provided by the user. The program stored in the recording medium may be compressed or uncompressed. The program is installed in the hard disk drive 908 from the recording medium, read into the RAM 903, and executed by the CPU 902. The program executed by the CPU 902 causes the communication terminal 910 to function as the communication terminal in each embodiment described above.

The programs shown above may be stored in an external storage medium. As storage media, in addition to the flexible disk 993 and CD-ROM 992, optical recording media such as DVD (Digital Versatile Disk) or PD (Phase Disk), magneto-optical recording media such as MD (MiniDisk), tape media, IC cards A semiconductor memory or the like can be used. In addition, an information sharing system may be provided as a program via a network by using a storage medium such as a hard disk or a RAM provided in a server system connected to a dedicated communication network or the Internet as a recording medium.

Although the present invention has been described with reference to the above embodiments, the present invention is not limited to the above-described embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

Note that the present invention enjoys the benefit of the priority claim based on the patent application of Japanese Patent Application No. 2013-0579904 filed on March 21, 2013 in Japan, and is described in the patent application. The contents are all included in this specification.

It can be used for mobile communication such as inter-vehicle communication, road-to-vehicle communication, and terminal-to-terminal communication.

DESCRIPTION OF SYMBOLS 100 ... Communication system 110 ... Reception terminal 120 ... Transmission terminal 130 ... Management terminal

Claims

A communication system having a receiving terminal, a plurality of transmitting terminals constituting a formation, and a management terminal,
The management terminal
A communication unit that performs wireless communication;
A data storage unit for storing data;
A convoy information storage unit for storing convoy information that is information relating to the convoy;
A data division arrangement determining unit for determining a data division method and a distributed arrangement method based on the formation information;
The data is divided into a plurality of partial data according to the determined division method, the partial data obtained by the division, transmission destination information in which the receiving terminal is set as a transmission destination, the partial data and the division source A data division arrangement unit that transmits a bundle having relation information with the data to the plurality of transmission terminals of the distributed arrangement destination determined by the determined distributed arrangement method through the communication unit of the own terminal;
Each of the transmitting terminals
A communication unit that performs wireless communication;
A bundle storage unit;
A bundle receiving unit for storing the bundle received by the communication unit of the terminal from the management terminal in the bundle storage unit of the terminal;
The bundle having the transmission destination information with the reception terminal set as a transmission destination is input from the bundle storage unit, and when the reception terminal is detected to be within a communicable range of the own terminal, the bundle is A bundle transmitting unit that transmits to the receiving terminal through the communication unit of the terminal,
The receiving terminal is
A communication unit that performs wireless communication;
A data storage unit;
A bundle storage unit;
A bundle receiving unit that stores the bundle received by the communication unit of the terminal from a plurality of the transmitting terminals in the bundle storage unit;
The bundle having the transmission destination information set as the transmission destination is input from the bundle storage unit of the local terminal, and based on the relationship information between the partial data in the bundle and the data of the division source, A communication system comprising: a data reconstruction unit that combines the partial data in a bundle to reconstruct the data of the division source and stores the reconstructed data in the data storage unit of the terminal itself.
A communication method executed by a communication system having a receiving terminal, a plurality of transmitting terminals constituting a formation, and a management terminal,
The management terminal determines a data division method and a distributed arrangement method to be transmitted to the receiving terminal based on the information on the convoy,
The management terminal divides the data into a plurality of partial data according to the determined division method, the partial data obtained by the division, transmission destination information in which the reception terminal is set as a transmission destination, and the partial A bundle having data and relationship information between the data of the division source is transmitted by wireless communication to the plurality of transmission terminals of the distributed arrangement destination determined by the determined distributed arrangement method,
Each of the transmitting terminals stores the bundle received from the management terminal, and transmits the bundle to the receiving terminal by wireless communication when detecting that the receiving terminal has entered the communicable range of the own terminal. And
The receiving terminal combines the partial data in the plurality of bundles based on the relationship information between the partial data in the bundle received from the plurality of transmitting terminals and the data of the division source. A communication method for reconfiguring the data.
A communication unit that performs wireless communication;
A data storage unit for storing data to be transmitted to the receiving terminal;
A formation information storage unit for storing formation information that is information relating to the formation composed of a plurality of transmission terminals;
A data division arrangement determining unit for determining a data division method and a distributed arrangement method based on the formation information;
The data is divided into a plurality of partial data according to the determined division method, the partial data obtained by the division, transmission destination information in which the receiving terminal is set as a transmission destination, the partial data and the division source A communication terminal having a data division arrangement unit that transmits, through the communication unit, a bundle having relation information with the data to the plurality of transmission terminals that are distributed arrangement destinations determined by the determined distribution arrangement method.
The formation information includes information representing the number of the transmission terminals that form the formation,
The communication terminal according to claim 3, wherein the data division arrangement determining unit determines the data division method and the distributed arrangement method based on the number of the transmission terminals forming the platoon.
The formation information includes information indicating the number of the transmission terminals that form the formation and position information of the transmission terminals,
4. The communication terminal according to claim 3, wherein the data division arrangement determining unit determines the data division method and the distributed arrangement method based on the number of the transmission terminals forming the platoon and the position of the transmission terminal. 5. .
The formation information includes information indicating the number of the transmission terminals that form the formation, position information of the transmission terminal, and information indicating characteristics of a road on which the formation is moving,
The data division arrangement determining unit, based on the number of the transmission terminals forming the platoon, the position of the transmission terminal, and the characteristics of the road on which the platoon is moving, the data division method and the distributed arrangement method, The communication terminal according to claim 3, wherein the communication terminal is determined.
The formation information includes information on a communication speed of the transmission terminal that forms the formation,
The data division arrangement determination unit determines the division method and the distributed arrangement method so as to arrange the partial data having a larger size for the transmission terminal with the higher communication speed. The communication terminal in any one.
The formation information includes one or more index values of the transmission terminals that form the formation,
The data division arrangement determination unit calculates an evaluation value for each of the transmission terminals forming the platoon using one or more index values of the transmission terminal and a predetermined evaluation function, and the evaluation value is equal to or greater than a threshold value 4. The communication terminal according to claim 3, wherein the transmission terminal or a certain number of the transmission terminals having higher evaluation values is determined, and the data division method and the distributed arrangement method are determined based on the determination result.
A computer constituting the communication terminal,
A communication unit that performs wireless communication;
A data storage unit for storing data to be transmitted to the receiving terminal;
A formation information storage unit for storing formation information that is information relating to the formation composed of a plurality of transmission terminals;
A data division arrangement determining unit for determining a data division method and a distributed arrangement method based on the formation information;
The data is divided into a plurality of partial data according to the determined division method, the partial data obtained by the division, transmission destination information in which the receiving terminal is set as a transmission destination, the partial data and the division source The program for functioning as a data division | segmentation arrangement | positioning part which transmits the bundle which has the relationship information with the said data to the said some transmission terminal of the distribution location determined by the determined distribution arrangement method through the said communication part.