JP2007335955A - Data communication system and data communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data communication system and a data communication device between devices capable of transmitting and receiving data reliably and quickly even in narrow-band data communication between communication devices. <P>SOLUTION: In a transmitter 2, an object data extraction section 5 extracts object data comprising required class information and data from a transmission request object, a data creation section 6 creates the extracted object data in a prescribed data format, and a compression processing section 7 compresses and processes the object data in the prescribed format for transmission. A receiver 4 restores the data by reverse processes. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a data communication system and a data communication apparatus for communicating data between communication apparatuses that are spaced apart and distributed.

  When data communication is performed between two communication devices that are separated and distributed, a network connection needs to be established between the communication devices. Even in this case, if data transmission / reception is possible and the desired data type, data format, data size, etc. cannot be handled by both communication devices, data communication cannot be performed or Data is invalid.

Therefore, conventionally, communication has been performed based on a communication method uniquely determined by a communication device manufacturer. Examples of communication methods include a method for determining whether or not a data transmission side device can transmit data, or a method for determining whether or not requested data can be transmitted, and a type of data that can be transmitted by the data transmission side device , A method for comparing the data type valid at the data receiving side device to determine the communication target device and the data type, the data type and number of data that can be transmitted by the data transmitting side device, and the data identification information There are methods for obtaining and communicating. Furthermore, some of these procedures are omitted or a method of executing a certain communication sequence by combining a plurality of methods is employed. (For example, see Patent Document 1)
On the other hand, in terms of processing corresponding to the amount of information, data can be transmitted and received between two communication devices, and the desired data type, data format, data size, etc. can be handled by both communication devices. Even in the state, the communication band is narrow (narrow-band communication path), for example, a network between the ground system and the train (between the ground and the vehicle), such as a train radio provided for communication related to train operation In this case, it is not suitable for handling a large amount of information such as images. If an attempt is made to obtain a service that handles images, the response to the service request is delayed, and the user may not be able to receive a satisfactory service. (For example, see Patent Document 2)
When the information targeted for multimedia is expressed in a digital format, when the amount of information is estimated as a digital information amount, the amount of information per character is 1 to 2 bytes in the case of characters. For audio, an information amount of 64 Kbits (telephone quality) per second is required, and for moving images, an amount of information of 100 Mbits (current television broadcast quality) per second or more is required. It is not realistic to handle such enormous information in digital form. Therefore, an information compression technique is used. For example, in the case of a videophone, H.264 has been internationally standardized by ITU-T (International Telecommunication Union Telecommunication Standardization Sector). 261 and H.264. H.263 standard video compression technology is used. In addition, according to the information compression technology of the MPEG1 standard, it is also possible to record image information together with audio information on a normal music CD (compact disc).

  Data types and data formats are closely related to software development. As is well known, in the field of software development, “object-oriented” technology that emphasizes data to be processed rather than processing procedures is actively adopted. Software based on object orientation is basically handled in units of modules called “objects” in which data and processing procedures for the data are integrated. Further, one software is formed by creating or combining a plurality of objects as necessary.

  Note that object orientation is realized by four basic technologies: “encapsulation”, “class / instance”, “class inheritance (inheritance)”, and “message passing”.

That is, encapsulation refers to integrating data and procedures (methods). Class refers to defining multiple objects in common. An instance represents an entity of an object belonging to a class (an object belonging to the same class, ie, an instance, basically has the same method, so there is no need to define each method individually). Inheritance means that another (for example, subordinate) class inherits what was defined in one class (when a new class is defined, only the difference from the defined class needs to be added or changed. ). Message passing refers to sending a message to an object to instruct a predetermined action. Since each object hides its own data, it is usually not possible to access the object by any means other than message passing.
JP 2005-218125 A [0002] JP-A-2005-223661 [0005]

  As described above, when data communication is performed between two communication devices, if the data is an object including data, the object is serialized (binary) together with the class information in the object to be transmitted. And send it in a predetermined file format. For this reason, there is a drawback that the amount of additional information such as the file format for the data is large and the data size (data amount) is large.

  In order to reduce the data size, it is conceivable to reduce additional information such as file format information added to the data, but there is a limit because it cannot be eliminated.

  In particular, when communicating in a narrow band, it is not suitable for handling a large amount of information such as images. Therefore, when handling a large amount of information, a situation occurs in which the data file must be divided and transmitted / received. To do. In that case, it is necessary to adjust the setting of the division procedure, the size of the divided data, and the like between communication devices, and complicated preprocessing is required.

  The present invention has been made in view of these circumstances, and provides a data communication system and a data communication apparatus between apparatuses that can transmit and receive data reliably and quickly even in narrowband data communication between communication apparatuses. The purpose is that.

A first feature of the data communication system according to the present invention is data having a transmitting device that transmits data and a receiving device that is connected to the transmitting device via a communication unit and receives data transmitted from the transmitting device. A communication system,
The transmission device extracts an object data consisting of necessary class information and data from a transmission request object, and data creation for creating the object data extracted by the object data extraction unit in a predetermined data format A compression processing unit that compresses the object data in a predetermined format created by the data creation unit, and a transmission unit that transmits the object data compressed by the compression processing unit,
The receiving device includes a receiving unit that receives the compressed object data transmitted from the transmitting device, a decompression processing unit that decompresses and restores the compression of the object data received by the receiving unit, An object data restoration unit that restores the class information and the data from the object data restored by the decompression processing unit, and a related object is generated from the class information restored by the object data restoration unit, and is also restored. A data communication system comprising: an object generation unit that sets the generated data as an object.

  A second feature of the data communication system according to the present invention is that the predetermined data format used when the data generation unit generates the object data extracted by the data extraction unit in a predetermined data format is CSV ( The data communication system is characterized in that it is in the format of Comma Separated Va1ue).

A third feature of the data communication system of the present invention is a data communication system for communicating data with each other between a plurality of communication devices arranged apart from each other.
Each of the communication devices is a data communication system including the above-described transmission device and reception device.

  A fourth feature of the data communication system according to the present invention is a data communication system characterized in that the communication apparatuses are connected by an independent method or an infrastructure method.

  The first feature of the data communication apparatus according to the present invention is that an object data extraction unit that extracts object data including necessary class information and data from a transmission request object, and the object data extracted by the object data extraction unit. A data creation unit that creates a predetermined data format, a compression processing unit that compresses the object data in a predetermined format created by the data creation unit, and the object data that is compressed by the compression processing unit A data communication apparatus comprising a transmitting unit that performs the above processing.

  A second feature of the data communication apparatus according to the present invention is that a receiving unit that receives object data, which is composed of class information and data, is transmitted from the transmitting apparatus and is compressed, and the object data received by the receiving unit. A decompression processing unit that decompresses and restores the object data, an object data restoration unit that restores the class information and the data from the object data restored by the decompression processing unit, and a restoration by the object data restoration unit The data communication apparatus further comprises an object generation unit that generates a related object from the class information and sets the restored data in the object.

  According to the present invention, it is possible to realize a data communication system and a data communication device between communication devices that can transmit and receive data reliably and quickly even in narrowband data communication between communication devices.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a functional block diagram schematically showing a system configuration of an embodiment of a data communication system for realizing a data transmission method according to the present invention.

  As shown in FIG. 1, a data communication system 1 for realizing a data transmission method includes a transmission device 2 on the transmission side and a communication means 3 (wired or wireless) arranged apart from the transmission device 2. It is comprised with the receiver 4 of the receiving side connected. Note that the bandwidth used for communication between the transmission device 2 and the reception device 4 is, for example, a narrow bandwidth of 9600 bps.

  The transmission apparatus 2 includes an object data extraction unit 5 that extracts object data including necessary class information and data from a transmission request object, and the object data extracted by the object data extraction unit 5 is in CSV (Comma Separated Value) format. A CSV data creating unit 6 for creating the data, a compression processing unit 7 for compressing the object data in the CSV format created by the CSV data creating unit 6, and the object data compressed by the compression processing unit 7 A transmission unit 8 for transmission is included. Each unit is controlled by a control unit (not shown) such as a CPU.

  Note that data in CSV (Comma Separated Values) file format (hereinafter, data in the CSV file format is simply referred to as CSV file) is a format in which description contents (data) are separated by a comma (,).

  The transmission device 2 is connected to the reception device 4 through a LAN line, the Internet, or the like as the communication means 3. In addition, since the data format transmitted from the transmission device 2 is a CSV file format, the reception device 4 is set in advance so as to be able to cope with it.

  The configuration of the receiving device 4 is a receiving unit 11 that receives the compressed object data transmitted from the transmitting device 2, and decompresses and restores the compression of the compressed object data received by the receiving unit 11. The decompression processing unit 12, the object data restoration unit 13 that restores class information and data to a CSV file from the restored object data decompressed by the decompression processing unit 12, and the object data restoration unit 13 An object generation unit 14 that generates an object corresponding to the request from the transmission request object by generating a related object from the class information and setting the restored data in the object is provided. Each unit is controlled by a control unit such as a CPU.

  As described in the background art section, a class refers to defining a plurality of objects in common. For example, an instance represents an entity of an object belonging to a class (an object belonging to the same class, that is, an instance basically has the same method, so there is no need to define each method individually). Inheritance means that another (for example, subordinate) class inherits what was defined in one class (when a new class is defined, only the difference from the defined class needs to be added or changed. ).

  Next, the flow of information processing in the data communication system 1 will be described step by step. FIG. 2 is a flowchart showing the flow of information processing in the above-described data communication system.

First, in the transmission apparatus 2, when the object data extraction unit 5 receives a data transmission request from the transmission request object, the object data extraction unit 5 class information / class information that is the minimum necessary information to be transmitted from the transmission request object. Extract data from an object as object data. (S1)
Next, the CSV data creation unit (data creation unit) 6 converts the extracted object data (class information / data) into a CSV file that is CSV format data (S2).

Next, the compression processing unit 7 performs reversible data compression processing on the CSV file using a known compression program. (S3)
Next, the transmission unit 8 transmits the compressed CSV file to the reception device 4 via the communication unit 3. (S4)
In the reception device 4, the reception unit 11 receives the CSV file transmitted via the communication unit 3. (S5)
Next, the decompression processing unit 12 decompresses the CSV file input from the reception unit 11 and returns it to CSV format data. (S6)
Next, the object data restoration unit 13 restores the class information and data from the CSV file and restores the object data extracted by the transmission device 2. (S7)
Next, the object generation unit 14 generates an object corresponding to the request from the transmission request object by generating a related object from the restored class information and setting the restored data in the object. (S8)
As described in the above steps, the CSV file transmitted from the transmission apparatus 2 to the reception apparatus 4 is a class that is the minimum necessary information to be transmitted, which is extracted from an object and unnecessary data is reduced. Information / data. Therefore, the data size is significantly smaller than when the object is transmitted as it is. Thereby, it is possible to sufficiently transmit even narrow-band communication.

(Second Embodiment)
In the data communication system 1 of the first embodiment described above, the transmission device 2 is the transmission side and the reception device 4 is the reception side. However, in the data communication system 1A of the second embodiment, both communication devices C ₁ and C _{2 are used.} Includes a transmission device 2 on the transmission side and a reception device 4 on the reception side. In FIG. 3, the same parts as those in FIG.

In the case of the data communication system 1 of the second embodiment, the communication device C ₁ and the communication device C ₂ both have a transmission device 2 as a transmission side and a reception device 4 as a reception side. That is, when transmitting from the communication device C ₁ to the communication device C ₂ , transmission is performed from the transmission device 2 of the communication device C ₁ , and reception is performed by the reception device 4 in the communication device C ₂ . On the other hand, when transmitting from the communication apparatus C ₁ to the communication apparatus C ₂ , the transmission is performed from the transmission apparatus 2 of the communication apparatus C ₂ , and the communication apparatus C ₁ receives the reception apparatus 4.

  In the case of the second embodiment, the communication step between the transmission device 2 and the reception device 4 can be used as it is in the first embodiment, and the description thereof is omitted.

Therefore, any of the communication devices C ₁ and C ₂ can transmit to the other communication device C ₁ and C _2, and can also communicate with each other at the same time.

Also in this case, the CSV file transmitted between the mutual communication devices C ₁ and C ₂ is class information / data that is the minimum necessary information to be transmitted, in which unnecessary data extracted from the object is reduced. . In other words, the data size is significantly smaller than when the object is transmitted as it is. Thereby, it is possible to sufficiently transmit even narrow-band communication.

(Third embodiment)
In the data communication system 1A of the second embodiment described above, the communication of the two communication devices C ₁ and C ₂ has been described. However, in the data communication system 1 of the third embodiment, three or more communication devices C ₁ , Communication in the case of C ₂ , C ₃ ... Will be described.

Each communication device _{C 1,} C 2, _{C 3} · · are used in the data communication system 1B of the third embodiment, each communication apparatus used in a data communication system 1A of the second embodiment described above _C 1, _{C 2} Thus, in the following description, the individual descriptions of the communication devices C ₁ , C ₂ , C ₃ .

That is, as shown in the schematic connection diagram in FIG. 4, the communication device C ₁ , the communication device C _2, and the communication device C ₃ are connected in an independent system (sometimes called an ad hoc format) network configuration. Yes. Therefore, each communication device (communication device C ₁ and the communication device C ₂ and the communication device C ₃₎ can communicate with both each other directly.

In addition to the independent method, an infrastructure method can also be used. In infrastructure mode, the communication device by mediating the radio base station (communication device C ₁ and the communication device C ₂ and the communication device C ₃₎ are both able to communicate directly with each other.

  Note that, in the case of the third embodiment as well, the step of communication between the transmission device 2 and the reception device 4 can be used as it is in the above-described first embodiment, and thus the description thereof is omitted.

  Also in the case of the third embodiment, the CSV file transmitted between the mutual communication devices is class information / data which is the minimum necessary information to be transmitted, which is extracted from the object and unnecessary data is reduced. . Therefore, the data size is significantly smaller than when the object is transmitted as it is. Thereby, it is possible to sufficiently transmit even narrow-band communication.

  In each embodiment, as described above, the CSV file format is used as the file format. However, the file format is not necessarily limited to the CSV file format as long as it can be expressed.

  In addition, the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a functional block diagram schematically showing a system configuration of a first embodiment of a data communication system for realizing a data transmission method according to the present invention. The flowchart which showed the flow of the information processing in the data communication system of 1st Embodiment. The functional block diagram which showed schematically the system configuration | structure of 2nd Embodiment concerning this invention. The functional block diagram which showed roughly the system configuration | structure of 3rd Embodiment concerning this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 1A, 1B ... Data communication system, 2 ... Transmission apparatus, 3 ... Communication means, 4 ... Reception apparatus, 5 ... Object data extraction part, 6 ... CSV data creation part, 7 ... Compression processing part, 8 ... Transmission part, DESCRIPTION OF SYMBOLS 11 ... Reception part, 12 ... Decompression processing part, 13 ... Object data restoration part, 14 ... Object generation part.

Claims (6)

A data communication system comprising: a transmission device that transmits data; and a reception device that is connected to the transmission device via communication means and receives data transmitted from the transmission device,
The transmission device extracts an object data consisting of necessary class information and data from a transmission request object, and data creation for creating the object data extracted by the object data extraction unit in a predetermined data format A compression processing unit that compresses the object data in a predetermined format created by the data creation unit, and a transmission unit that transmits the object data compressed by the compression processing unit,
The receiving device includes a receiving unit that receives the compressed object data transmitted from the transmitting device, a decompression processing unit that decompresses and restores the compression of the object data received by the receiving unit, An object data restoration unit that restores the class information and the data from the object data restored by the decompression processing unit, and a related object is generated from the class information restored by the object data restoration unit, and is also restored. A data communication system, comprising: an object generation unit that sets the processed data as an object.   The predetermined data format used when the data generation unit generates the object data extracted by the data extraction unit in a predetermined data format is a CSV (Comma Separated Value) format. The data communication system described. A data communication system that communicates data with each other between a plurality of communication devices that are spaced apart from each other,
A data communication system, wherein each of the communication devices includes a transmission device and a reception device described in claim 1.   4. The data communication system according to claim 3, wherein the communication devices are connected by an independent method or an infrastructure method.   An object data extraction unit that extracts object data including necessary class information and data from the transmission request object, a data creation unit that creates the object data extracted by the object data extraction unit in a predetermined data format, and the data A data communication apparatus comprising: a compression processing unit that compresses the object data in a predetermined format created by a creation unit; and a transmission unit that transmits the object data compressed by the compression processing unit.   A receiving unit that receives class data and data that is transmitted from the transmission device and is subjected to compression processing, a decompression processing unit that decompresses and restores the compression of the object data received by the reception unit, and the decompression An object data restoration unit that restores the class information and the data from the object data restored by the processing unit, and a related object is generated from the class information restored by the object data restoration unit. A data communication apparatus comprising an object generation unit that sets the data as an object.

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