JP2002217948A - Data communication method and data communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data communication system which can conduct error control for packet missing in cable line section, without degrading communication efficiency. SOLUTION: This system is equipped with a mobile terminal communication control means 12, which provides an higher one in the communication order with connection control data and data communication interface selection between the termination of a communication terminal device 1 and between the termination of a server terminal device 3, on the occasion of data communication between the communication terminal device 1 and the server terminal device 3, that are respectively connected to a relay device 2 by a radio communication line 4 and a cable communication line 5, error control means 13 and 22, which conduct error control for communication data between the communication terminal device 1 and the relay device 2, a communication control relay means 21, which conducts communication packet conversion according to the difference in communication protocols between the communication terminal device 1 and the server terminal device 3, and protocol processing means 24 and 32, which have a data communication function accompanied with an error control between the transit device 2 and the server terminal device 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a data communication method and a data communication system for performing data communication between a communication terminal device and a server terminal device via a communication line having different communication characteristics via a relay device.

[0002]

2. Description of the Related Art Conventionally, this kind of data communication system has
It is used for the purpose of realizing error-free data transfer between communication end points in a communication line or a communication network in which a communication packet which is connection control data may be lost during data transfer.

For example, in the communication system disclosed in Japanese Patent Application Laid-Open No. 5-160831, error control is efficiently performed in ISDN (Integrated Services Digital Communication Network).
A first wireless communication adapter device wired to one of the signal communication networks, a first wireless communication device wirelessly connected to the first wireless communication adapter device, and a wired connection to the first wireless communication device; A second wireless communication adapter device wired to the other of the signal communication network, and a second wireless communication device wirelessly connected to the second wireless communication adapter device. , A second terminal device wired to the second wireless communication device, and a first wireless communication adapter and a second wireless communication device only between the first wireless communication device and the second wireless communication device. Error control with other wireless communication adapters is performed, and error control in other devices is omitted to reduce the processing required for error control.

Incidentally, another well-known technique related to error control in data communication is disclosed in JP-A-6-2686.
No. 34 discloses a wireless communication system and the like.

[0005]

In the case of the above-mentioned communication system, the first wireless communication adapter device and the second wireless communication adapter device, the first terminal device and the first wireless communication device, the second wireless communication adapter device, and the second wireless communication adapter device. Since error control is not performed between the terminal device and the second wireless communication device, error control is not possible if packet loss occurs in these sections. Therefore, error control cannot be performed for packet loss in a wired line section. There is a problem.

Further, the error control mechanism of the first terminal device and the second terminal device recognizes the error control in the first wireless communication device and the second wireless communication device and the processing state of the error control mechanism there. And the occurrence of useless processing and communication cannot be avoided. Therefore, even if a unique error control mechanism is provided between the first terminal device and the second terminal device, the communication efficiency may be extremely reduced. There is a problem that can occur.

More specifically, when a transmission packet error detection based on a retransmission timer timeout and an error recovery mechanism based on retransmission are employed as error control methods between the terminal device and the radio communication device, the timeout period is set. Is set based on the time required for the delivery confirmation notification from the receiving side to the communication packet transmitted in the past so as to be able to respond to changes in the characteristics of the commonly used communication network,
When communicating a communication packet between terminal devices, if packet loss occurs continuously between the wireless communication device and the wireless communication adapter due to deterioration of the radio wave condition in the wireless communication space, the packet is transmitted between the wireless communication device and the wireless communication adapter. The timeout wait and the retransmission of the communication packet in the side device are repeated, and the time required for the communication packet delivery processing in this section suddenly increases. In addition, if the retransmission timer of the wireless communication device times out before the delivery of the communication packet between the wireless communication device and the wireless communication adapter is completed,
Even when the communication packet is not actually lost and the retransmission is repeated between the wireless communication device and the wireless communication adapter, the transmitting terminal determines that the packet has been lost and retransmits the communication packet. If the initially transmitted communication packet is delivered without error to the receiving terminal device, processing and communication in each device relating to the retransmitted communication packet are completely wasted, and the communication efficiency is degraded.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a technical problem of the present invention is to provide a data communication system capable of performing error control on packet loss in a wired line section without reducing communication efficiency. It is to provide a method and a data communication system.

[0009]

According to the present invention, there is provided a data communication method for performing data communication between a communication terminal device and a server terminal device connected to a relay device via a wireless line and a wired line, respectively. , The connection control data between the terminal of the communication terminal device and the terminal of the server terminal device and the selection of an interface for data communication are provided in accordance with the higher order in the communication order, and a radio link is provided between the communication terminal device and the relay device. A communication data error control step of performing error control of the communication data via the communication device, and a first communication packet for the server terminal device received from the communication terminal device as connection control data to a communication protocol between the relay device and the server terminal device. A first conversion step for performing a first conversion together; and a first conversion step for the communication terminal device received from the server terminal device as connection control data. A second conversion step of performing a second conversion of the communication packet according to the communication protocol between the relay apparatus and the communication terminal apparatus, and a step between the relay apparatus and the server terminal apparatus based on the connection control data having undergone the first conversion. A data communication step of performing data communication with error control via a wired line.

In this data communication method, in the communication data error control step, the size of the first communication packet is controlled in accordance with the error history of the second communication packet received in the past, or the communication terminal device and the relay device It is preferable to use a connection identifier as connection control data when performing data communication between them.

According to the present invention, on the other hand, the relay device and the communication terminal device are connected by a wireless line, and the relay device and the server terminal device are connected by a wired line. And a data communication system capable of performing data communication between the server terminal devices, wherein the communication terminal device selects connection control data and an interface for data communication between the terminal device of the own device and the terminal device of the server terminal device. Communication control means for providing to the relay device via the wireless line in accordance with the higher order in the communication order, the relay device performs error control of communication data based on connection control data and interface selection from the communication terminal device. Error control means for performing, and a first communication packet for the server terminal device received from the communication terminal device as connection control data. And a first conversion means for performing a first transformation in accordance with the communication protocol between the server terminal apparatus,
A second conversion unit for performing a second conversion of a second communication packet for the communication terminal device received from the server terminal device as connection control data in accordance with the communication protocol between the own device and the communication terminal device; The relay device and the server terminal device can obtain a data communication system including data communication means for performing data communication with error control via a wired line based on the connection control data that has undergone the first conversion.

According to the present invention, in the above data communication system, the first conversion means and the second conversion means are
A data communication system provided in the communication control relay unit that performs the first conversion and the second conversion is obtained.

Further, according to the present invention, in any of the above data communication systems, the error control means may be configured to perform the first control in accordance with the error history regarding the second communication packet received in the past.
A data communication system for controlling the size of the communication packet of the above is obtained.

In addition, according to the present invention, in any one of the above data communication systems, the communication control means can obtain a data communication system using a connection identifier as connection control data when performing data communication between the own device and the relay device. Can be

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A data communication method and a data communication system according to the present invention will be described below in detail with reference to the drawings.

First, the outline of the data communication method of the present invention will be briefly described. In the data communication method, when performing data communication between a communication terminal device and a server terminal device connected to a relay device by a wireless line and a wired line, respectively, the communication terminal device terminates the communication terminal device and the server terminal device. A communication data error that provides connection control data between terminals and an interface selection for data communication according to a higher order in communication order, and performs error control of communication data between a communication terminal device and a relay device via a wireless line. A control step, and a first conversion step of performing a first conversion of a first communication packet for the server terminal device received from the communication terminal device as connection control data in accordance with a communication protocol between the relay device and the server terminal device; The second communication packet for the communication terminal device received from the server terminal device as connection control data is transmitted between the relay device and the communication terminal device. A second conversion step of performing a second conversion in accordance with a protocol, and performing data communication with error control between the relay device and the server terminal device via a wired line based on the connection control data having undergone the first conversion. And a data communication step.

However, in the communication data error control step, the size of the first communication packet is controlled according to the error history of the second communication packet received in the past, or the communication terminal device and the relay A connection identifier may be used as connection control data when performing data communication between devices.

According to such a data communication method, in data communication between a communication terminal device and a server terminal device via a relay device through a wireless communication line and a wired communication line network, control information necessary for protocol control is exchanged. In order to perform protocol control corresponding to dynamic line quality fluctuations of low-quality and unstable wireless communication lines, it is performed only in the wired communication network section, minimizing protocol overhead in the wireless communication line section, It is possible to perform error control with respect to packet loss in a section of a wired communication network without lowering communication efficiency.

FIG. 1 is a block diagram showing a basic configuration of a data communication system according to an embodiment to which the data communication method is applied. This data communication system includes a communication terminal device 1 having a wireless communication function, a relay device 2 connected to the communication terminal device 1 by a wireless communication line 4, and a relay device 2 connected to the relay device 2 by a wired communication line network 5. Wired LA
And N server environments 3.

The communication terminal device 1 includes a communication service unit 11, a mobile terminal communication control unit 12, an error control unit 13, a physical interface control unit 14, and a storage unit 15. The relay device 2 includes a communication control relay unit 21, an error control unit 22, a physical interface control unit 23, a protocol processing unit 24, and a storage unit 25. Further, the server terminal device 3 includes a communication service unit 31 and a protocol processing unit 32.

More specifically, in the communication terminal device 1, the storage unit 15 stores a packet reception history including the size of the communication packet received by the error control unit 13, the time when the packet was received, and the presence or absence of an error in the communication packet. And
The received data and the like are stored in addition to the unconfirmed transmission packet information indicating the contents of the communication packet for which the reception success notification has not yet been confirmed among the transmitted communication packets. The communication service means 11 is an ftp or tel on the Internet.
A communication service unit 3 provided in the server terminal device 3 by an application program (AP) for providing a service involving communication such as a net, a web browser, or the like.
1 by providing data communication with each other to provide a service to the user.

The mobile terminal communication control means 12
An interface for data communication that manages connections with the communication control relay means 21 provided on the basis of connection identifiers used as connection control data for each connection, and guarantees reliability to the communication service means 11 I will provide a.
Also, the mobile terminal communication control means 12 is a communication service means 1
1 receives a connection start request including connection destination information relating to the server terminal device 3, a connection end request including a connection identifier, a data transmission request including a connection identifier and data, and a data reception request including a connection identifier.

That is, the mobile terminal communication control means 12 generates a connection identifier for identifying the connection start request at the time of the connection start request, and notifies the error control means 13 of the connection identifier and the identifier of the requester of the connection start (hereinafter referred to as a request). Request for transmission of a connection start message including the connection destination information included in the connection start request), and when the error control means 13 notifies the connection start success message with the connection identifier,
The communication service unit 11 is notified of the connection success and the connection identifier by the connection start request. Here, examples of the connection destination information and the requester identifier include a host name or an IP address for identifying the server terminal device 3 in the TCP / IP protocol.
An address and a port number for identifying the communication service means 31 provided in the server terminal device 3 are exemplified.

The mobile terminal communication control means 12 requests the error control means 13 to transmit a connection end message including the connection identifier included in the connection end request at the time of the connection end request. Is notified, the communication service means 11 is notified of the end of the connection by the connection end request, and the connection identifier is released.

Further, the mobile terminal communication control means 12 requests the error control means 13 to transmit a data transmission message including the connection identifier and the data included in the data transmission request when the data transmission request is issued. The received data corresponding to the connection identifier included in the data reception request is extracted from the storage unit 15 and delivered to the communication service unit 11 that has issued the data reception request, but the extracted reception data is deleted from the storage unit 15. In addition, the mobile terminal communication control means 12 additionally stores the data in the reception data storage area of the storage means 15 corresponding to the connection identifier in the notification of the data reception including the connection identifier and the data from the error control means 13.

Upon receiving a transmission request such as a connection start message, a connection end message, a data transmission message, etc., the error control means 13 determines an optimum packet length based on the packet reception history of the wireless communication line stored in the storage means 15. The data to be calculated and transmitted are divided by the optimal packet length, and for each of the divided data (hereinafter, referred to as divided transmission data), a connection identifier and information indicating a position from the head of the data (hereinafter, referred to as a divided data). , Offset information),
It generates a communication packet including control information such as packet error check information for detecting a packet error, and requests the physical interface control means 14 to transmit the communication packet. Here, as an example of calculating the optimum packet length, there is a case in which the frame error rate in a past fixed time is calculated, and the value of the optimum packet length is reduced when the value exceeds a certain threshold.

The error control means 13 stores the contents of the once-transmitted communication packet in the storage means 15 as unconfirmed transmission packet information, and stores the contents of the communication packet created by the error control means 22 provided in the relay device 2. When the reception success notification is received, the contents of the communication packet stored as the unconfirmed transmission packet information in the storage unit 15 are deleted. However, the failure notification is received here, or the communication is performed before a predetermined time elapses after the transmission of the communication packet. If the packet reception success notification is not received, it is considered that the transmission of the communication packet has failed, and the optimum packet length (second packet length) is again determined based on the packet error history of the wireless communication line 4 stored in the storage unit 15. The optimum packet length is calculated and included in the communication packet stored as the unconfirmed transmission packet information in the storage unit 15. Dividing the divided communication data by the length of the second optimum packet length, and generating a communication packet including control information such as a connection identifier and offset information for each of the second divided communication data as the divided communication data. ,
It requests the physical interface control means 14 to transmit the communication packet.

Further, when the error control means 13 receives a communication packet composed of the connection identifier, the offset information, the packet error check information and the data generated by the error control means 22 of the relay device 2, the error control means 13 extracts the packet error check information from the packet. A check is performed to determine whether or not the communication packet is incorrect, and the processing described below is performed based on whether or not the communication packet is incorrect.

That is, when the communication packet is not erroneous, the error control means 13 creates a reception success communication packet including the connection identifier and the offset information, and requests the physical interface control means 14 to transmit the reception success communication packet. Further, the data of the communication packet is stored together with the offset information in the primary storage area of the received data corresponding to the connection identifier of the storage means 15, and the data of the data size is received from the offset value indicated by the offset information; The packet reception history concerning the communication packet is stored. At this time, if there is a block of data continuously received from the head among data corresponding to the connection identifier stored in the primary storage area of the received data (hereinafter, referred to as a reception completion data block), The reception completion data block is taken out from the primary storage area of the reception data, the connection identifier and the reception completion data block are notified of the data reception to the mobile terminal communication control means 12, and then the reception completion data block is retrieved from the reception data primary storage area. Delete
The data following the reception completion data block in the primary storage area of the reception data is set as the head of the primary storage area of the reception data. If the communication packet is incorrect, a reception failure notification packet including the connection identifier and the offset information is created, and the physical interface control unit 14 is requested to transmit the reception failure notification packet.

The physical interface control means 14 performs communication of a communication packet with the physical interface control means 23 provided in the relay device 2.
When a request for transmission of a communication packet is received from the relay device 2, the communication packet is transmitted to the physical interface control unit 23 of the relay device 2 through the wireless communication line 4, and when the communication packet is received from the physical interface control unit 23 of the relay device 2, an error occurs. The controller 13 is notified of the reception of the frame.

On the other hand, in the relay device 2, the storage means 25
Indicates the size of the communication packet received by the error control means 22, the time at which the packet was received, the packet reception history including the presence or absence of an error in the communication packet, and the reception success notification among the packets transmitted to the communication terminal device 1. Unconfirmed transmission packet information that stores the contents of communication packets that have not been stored, correspondence of connection identifiers, and the like are stored.

The communication control relay means 21 is provided with the error control means 2
When the connection start message including the connection destination information, the requester identifier, and the connection identifier created by the mobile terminal communication control unit 12 of the communication terminal device 1 is notified from the connection identifier 2, the connection identifier (hereinafter, the connection identifier) for identifying the connection request. 1), and sends a connection request to the communication protocol processing unit 24 together with the first connection identifier, the connection destination information, and the requester identifier. If the connection request succeeds, the communication protocol processing unit 24 notifies the success of the connection request and the second connection identifier, and stores the correspondence between the first connection identifier and the second connection identifier in the storage unit 25, and A request for transmission of a connection start success message including the connection identifier is made to 22.
Here, when a connection end message including the connection identifier generated by the mobile terminal communication control unit 12 of the communication terminal device 1 is notified from the error control unit 22, the communication control relay unit 21
Reads out the second connection identifier corresponding to the connection identifier from the storage unit 25 and makes a connection termination request to the communication protocol processing unit 24 together with the second connection identifier.
If this connection termination request is successful, the transmission request of the connection termination success message including the connection identifier is made to the error control unit 22, and thereafter, the correspondence between the connection identifier and the second connection identifier is deleted from the storage unit 25.

The communication control relay means 21 reads the second connection identifier corresponding to the connection identifier from the storage means 25 upon notification of data reception accompanied by the connection identifier and data from the error control means 22, and performs communication protocol processing. Means 2
4, a data transfer request is made together with the second connection identifier,
Storage unit 25 upon notification of data reception accompanied by the second connection identifier and data from communication protocol processing unit 24
, The connection identifier corresponding to the second connection identifier is read out, and a transmission request of the received data is sent to the error control means 22 together with the connection identifier.

When notified of the connection start success message, the connection end success message, and the transmission request of the data transmission message, the error control means 22 determines the error based on the frame reception history of the wireless communication line 4 stored in the storage means 25. Calculates the optimal packet length, divides the data to be transmitted by the optimal packet length, and for each of the divided transmission data, the connection identifier, offset information indicating the position from the head of the data, etc. A communication packet including the control information is generated, and the physical interface control unit 14 is requested to transmit the communication packet.

The error control means 22 stores the contents of the once-transmitted communication packet in the storage means 25 as unconfirmed transmission packet information, and notifies the error control means 13 of the communication terminal device 1 of the successful reception of the communication packet. Upon receipt,
The contents of the communication packet stored as the unconfirmed transmission packet information in the storage unit 25 are deleted. Here, a failure notification is received, or a communication packet reception success notification is received before a predetermined time has elapsed after the transmission of the communication packet. Otherwise, it is considered that transmission of the communication packet has failed,
Again, the optimum packet length (second optimum packet length) is calculated based on the frame error history of the wireless communication line 4 stored in the storage unit 25, and the communication stored as the unconfirmed transmission packet information in the storage unit 25 is calculated. Divided communication data included in the packet is divided by the second optimal packet length, and control information such as a connection identifier and offset information is provided for each of the second divided communication data that is the divided communication data. Is generated, and a request is made to the physical interface control means 23 to transmit the communication packet.

Further, when the error control means 22 receives a communication packet including the connection identifier, the offset information, and the data generated by the error control means 13 of the communication terminal device 1, it determines whether the communication packet has been successfully received. The process described below is performed depending on whether the process has failed.

That is, if the communication packet is successfully received, the error control means 22 creates a reception success notification packet including the connection identifier and the offset information, and transmits the reception success notification packet to the physical interface control means 23. And further stores the data of the communication packet together with the offset information in the primary storage area of the received data corresponding to the connection identifier of the storage means 25, and that the data of the data size from the offset value indicated by the offset information is received. Record At this time, of the data corresponding to the connection identifier stored in the primary storage area of the received data,
If there is a block of data received continuously from the beginning (reception completion data block), the reception completion data block is taken out from the primary storage area of the reception data, and the communication control relay unit 21 is transmitted together with the connection identifier and the reception completion data block.
Notification of data reception, and thereafter delete the reception completion data block from the primary storage area of the reception data, and replace the next data of the reception completion data block in the primary storage area of the reception data with the head of the primary storage area of the reception data. I do.
Then, when the reception of the communication packet fails, a reception failure notification packet including the connection identifier and the offset information is created, and the physical interface control unit 23 is requested to transmit the reception failure notification packet.

The physical interface control means 23 performs frame-by-frame data communication having an error detection function with the physical interface control means 14 of the communication terminal device 1. Upon receiving the request, the communication packet is framed and transmitted to the physical interface control means 14 of the communication terminal device 1,
When a frame is received from the physical interface control means 14 of the communication terminal device 1, it is checked whether or not the frame has been received without error. The size of the frame, the time at which it was received, the result of the reception of the frame (reception success or The information consisting of (failure of reception) is stored as a frame reception history in the storage unit 25, and the frame is notified to the error control unit 22.

The communication protocol processing means 24 manages the connection based on the second connection identifier for each connection with the communication protocol processing means 32 provided in the server terminal device 3, and To provide a data communication function that guarantees reliability. Here, examples of the communication protocol processing unit 24 include TCP / IP and Ether.
net (R) driver set, the second
Is a socket ID in a socket interface for using TCP / IP.

The communication protocol processing means 24 sends the first connection identifier, connection destination information,
When a connection request with a requester identifier is received, a connection request is sent to the connection destination obtained from the connection destination information using the sender as the request identifier. When the connection request is successful, a second connection identifier is generated, and the success of the connection request is notified to the communication control relay means 21 together with the first connection identifier and the second connection identifier, and the second connection identifier, A set of requester identifiers is stored as relay information. Similarly, for the disconnection request and the data communication request, the request is transferred to the connection destination obtained from the connection destination information with the sender as the requester identifier associated with each request. When the disconnection request is successful, the relay information related to the second connection identifier accompanying the disconnection request is deleted from the storage unit 25, and the second connection identifier is released.

When the communication protocol processing unit 24 receives the communication packet through the wired communication network 5, the communication protocol processing unit 24 stores, in the requester identifier of the relay information stored in the storage unit 25, the destination of the transmission packet included in the communication packet. It is checked whether or not there is a match with the identifier. If there is a match with the requester identifier, the second connection identifier corresponding to the requester identifier is read from the storage means 25 and communicated to the communication control relay means 21. Notification of data reception is performed together with the data included in the packet and the second connection identifier.

On the other hand, in the server terminal 3, the communication service means 31 uses ftp or tel on the Internet.
An application program (AP) that provides a service involving communication, such as a net and a web browser, and provides a service to a user by performing mutual data communication with a communication service unit 11 provided in the communication terminal device 1. .

The protocol processing means 32 manages a connection based on the second connection identifier for each connection with the protocol processing means 24 of the relay apparatus 2 and provides the communication service means 31 with data whose reliability is guaranteed. Provides communication functions.

In short, in this data communication system,
The relay device 2 and the communication terminal device 1 are connected by a wireless communication line 4, and the relay device 2 and the server terminal device 3 are connected by a wired communication line network 5. In the configuration in which data communication is performed between the devices 3, the communication terminal device 1 ranks the connection control data and the interface selection for data communication between the terminal device of its own device and the terminal device of the server terminal device in the order of communication. The mobile terminal communication control means 12 is provided as communication control means for providing to the relay device 2 via the wireless communication line 4 according to the type of connection, and the relay device 2 has connection control data from the communication terminal device 1 and interface selection. Control means 22 (which cooperates with error control means 13 of communication terminal device 1) for performing error control of communication data based on connection control data First conversion means for performing a first conversion of a first communication packet for the server terminal device 3 received from the communication terminal device 1 in accordance with a communication protocol between itself and the server terminal device 3, and a server as connection control data The second for the communication terminal device 1 received from the terminal device 3
And a communication control relay unit 21 having a second conversion unit for performing a second conversion of the communication packet according to the communication protocol between the own device and the communication terminal device 1. 3 includes protocol processing means 24 and 32 as data communication means for performing data communication with error control via the wired communication line 5 based on the connection control data having undergone the first conversion.
The error control means 22 controls the size of the first communication packet in accordance with the error history of the second communication packet received in the past, and the mobile terminal communication control means 12 establishes connection when data communication between the own apparatus and the relay apparatus 2 is performed. The connection identifier is used as control data.

Next, the basic operation of the data communication system will be described. The basic operation here is composed of three operations by a connection operation, a disconnection operation, and a data communication operation.

However, in this data communication system, when the ftp client program is used as the communication service means 11 and the ftp server program is used as the communication service means 31, data is transferred from the ftp client program to the ftp server program. The case will be described. Also, the protocol processing means 24,
Reference numeral 32 denotes a set of a data link control protocol of a network connected to TCP / IP.

FIG. 2 is a flowchart showing a connection operation process in the data communication system. That is, in the case of the connection operation, the communication service unit 11 which is an ftp client program in the communication terminal device 1 includes the connection destination information regarding the server terminal device 3 in the mobile terminal communication control unit 12 in the same format as the connection procedure in the socket interface, for example. (Host name of server terminal 3 and ft
When a connection start request is generated (including a port number for communicating with the p server program) (step A1), the mobile terminal communication control means 12 generates a connection identifier for identifying the connection start request (step A2), and generates an error. A request is sent to the control means 13 to transmit a connection start message including the connection destination information including the host name and port number of the server terminal device 3 and the connection identifier included in the connection start request (step A3). Thereby, the connection start message is notified to the error control means 13, the physical interface control means 14, the physical interface control means 23, and the communication control relay means 21 via the error control means 22. The operations relating to the means 13, the physical interface control means 14, the physical interface control means 23, and the error control means 22 are the same as the data communication operations of the above-described respective units, and will not be described here.

Next, in the relay device 2, the communication control relay means 21 receives the connection start message including the connection destination information including the host name and the port number of the server terminal device 3 and the connection identifier (step B1). The communication control relay means 21 issues a connection request to the communication protocol processing means 24 together with the connection destination information. Communication protocol processing means 24
Performs connection processing (step B2) with the communication protocol processing means 32 from the connection destination information using, for example, a socket interface, and determines whether or not the connection is successful (step B3). When the connection is successful, the success of the connection request and the second connection identifier are notified to the communication control relay means 21, and the communication control relay means 21 stores the correspondence between the connection identifier and the second connection identifier. 25 (step B4), and after requesting the error control means 22 to transmit a connection start success message including the connection identifier (step B5) (which may be performed to the communication terminal device 1), the processing is performed. finish. Thereby, the connection start success message is transmitted to the error control unit 22.
Is notified to the mobile terminal communication control means 12 via the physical interface control means 23, the physical interface control means 14, and the error control means 13, where the error control means 22, the physical interface control means 23, The operations relating to the physical interface control unit 14 and the error control unit 13 are the same as the data communication operations of the above-described units, and thus will not be described here.

In the communication terminal device 1, after the mobile terminal communication control means 12 requests the error control means 13 to transmit a connection start message (step A3), the error control means 13 sends a connection including the connection identifier. It is determined whether a start success message has been received (step A).
4) As a result, if not notified, the process is terminated. If notified, the communication service unit 11 notifies the communication service unit 11 of a successful connection and a connection identifier notification (step A).
After performing step 5), the process ends.

FIG. 3 is a flowchart showing a disconnection operation process in the data communication system. However, the disconnection operation in which the connection identifier is specified here is performed after the connection operation relating to the connection identifier and before the disconnection operation.
That is, in the case of the disconnection operation, in the communication terminal device 1, the communication service means 11 issues a connection end request including the connection identifier to the mobile terminal communication control means 12 in the same format as, for example, the disconnection procedure of the socket interface (step D1). Then, the mobile terminal communication control means 12 requests the error control means 13 to transmit a connection end message including the connection identifier included in the connection end request (step D2). As a result, the connection end message is notified to the error control means 13, the physical interface control means 14, the physical interface control means 23, and the communication control relay means 21 via the error control means 22. Control means 13
The operations relating to the physical interface control means 14, the physical interface control means 23, and the error control means 22 are the same as the above-described data communication operations of the respective units, and will not be described here.

Next, in the relay device 2, the communication control relay unit 21 receives a connection end message including the connection identifier (step E 1), and the communication control relay unit 21 stores the connection end message corresponding to the connection identifier from the storage unit 25. 2 is read out, and the second
A connection termination request is made together with the connection identifier of. The communication protocol processing means 24 performs a connection termination process (step E2) identified by the second connection identifier in the same format as the socket interface disconnection procedure, for example, and thereafter determines whether or not the packet has been successfully received. (Step E3)
As a result, if the connection has not been received, the process ends. If the connection has been successfully received, the success of the connection end request and the second connection identifier are notified to the communication control relay unit 21. The correspondence with the second connection identifier is deleted from the storage means 25 and packet transmission (step E4) is performed, and a request for transmission of a connection end success message including the connection identifier (step E5) to the error control means 22 (communication terminal) (May be performed on the device 1), and then terminates the processing. As a result, the connection end success message is transmitted to the error control unit 22 and the physical interface control unit 23.
, The physical interface control means 14 and the mobile terminal communication control means 12 via the error control means 13, where the error control means 22, the physical interface control means 23, and the physical interface control means 14 are notified. ,
The operation related to the error control means 13 is the same as the operation of the data communication of each unit described above, and thus the description is omitted here.

In the communication terminal device 1, after the mobile terminal communication control means 12 requests the error control means 13 to transmit a connection end message (step D2), the error control means 13 sends a connection including the connection identifier. It is determined whether the end success message has been received (step D).
3) As a result, if not notified, the process is terminated. If notified, the communication service means 11 is notified of the connection end by a connection end request (step D4), and the connection identifier is released (step D5). To end the process.

The data communication operation process in this data communication system will be described below. This data communication operation is performed from the communication terminal device 1 to the server terminal device 3 and from the server terminal device 3 to the communication terminal device 1. The data communication operation is performed after the connection operation relating to the connection identifier and before the disconnection operation.

FIG. 4 is a flow chart showing a data communication operation from the communication terminal device 1 to the server terminal device 3 as a data communication operation process in the data communication system. However, here, a case where 1000-byte data is transmitted from the communication terminal device 1 to the server terminal device 3 will be described.

That is, in the case of this data communication operation, in the communication terminal device 1, the communication service means 11 transmits the data including the connection identifier and the data to the mobile terminal communication control means 12 in the same format as, for example, the data transmission of the socket interface. Request for data transmission (step G1)
Is performed, the mobile terminal communication control means 12 makes the error control means 1
Request for transmission of a data transmission message including the connection identifier and the data included in the data transmission request to the data transmission request. When receiving the data transmission request including the connection identifier and the data, the error control unit 13 calculates the optimum packet length based on the frame reception history of the wireless communication line 4 stored in the storage unit 15 and converts the data into the optimum packet length. A communication packet comprising a connection identifier and offset information indicating a position from the beginning of the data from the start of connection of the divided transmission data for each of the divided transmission data that is data divided and divided by the length. Create a packet that generates
2), and requests the physical interface control means 14 to transmit a communication packet.

Here, for example, if the optimum packet length is 300
If the data is bytes, the size of the data from the beginning is 300 bytes, 300 bytes, 300 bytes, 10 bytes, respectively.
It is divided into four 0 bytes (the divided data is referred to as data A, data B, data C, and data D, respectively),
[Data A, CID,
1], [Data B, CID, 301], [Data C, C
ID, 601] and [Data D, CID, 901] can be exemplified.

The error control means 13 requests the physical interface control means 14 to transmit these four communication packets, and stores the contents of these communication packets in the storage means 15 as unconfirmed transmission packet information. The contents storage (step G3) is performed.

Further, the physical interface control means 14
Receives a request for transmission of a communication packet from the error control unit 13, adds a check bit for error detection to the communication packet to form a frame, and transmits a frame to the physical interface control unit 23 of the relay device 2 ( Step G4) is performed.

Next, in the relay device 2, the physical interface control means 23 receives a frame from the physical interface control means 14 of the communication terminal device 1 (step H1).
Then, it is checked whether or not the frame has been received without error from the check bits for error detection, and information including the size of the frame, the time when the frame was received, and the result of reception of the frame (reception success or reception failure). Is stored in the storage unit 25 as a frame reception history, thereby performing the process of storing the frame reception history (step H2), and notifies the error control unit 22 of the communication packet of the frame. Here, it is assumed that, for example, the reception of the communication packets of data A, data B, and data D succeeds, and the reception of the communication packet of data C fails.

Thereafter, the error control means 22 determines whether the communication packet has been received without error (whether the reception of the communication packet has succeeded or failed) (step H3). If the reception has failed, a reception failure notification packet including a connection identifier and offset information is created, and a request for transmission of a reception failure notification packet is sent to the physical interface control means 23 (step H9). If the communication packet has been successfully received, a reception success notification packet including the connection identifier and the offset information is created, and a request for transmission of the reception success notification packet is sent to the physical interface control means 23 (step H4). Stores communication packet data together with offset information in the primary storage area of received data corresponding to 25 connection identifiers Performs a process of storing the packets in the primary storage area by recording that the data size of data from the offset value indicated by the offset information has been received (step H5).

For example, the error control means 22 creates a reception failure notification packet consisting of [CID, 601] in response to the data C packet reception failure, and requests the physical interface control means 23 to transmit this reception failure notification packet. At the same time, [CID, 1] and [CID, 30] respectively correspond to successful reception of data A, data B, and data D.
1] and [CID, 901], and requests the physical interface control means 23 to transmit such a reception success notification packet. For example, as shown in [1-600, 901-1000] A case where the fact that data of the size of the data is received from the offset value is stored can be exemplified.

At this time, among the data corresponding to the connection identifier stored in the primary storage area of the received data, it is determined whether or not there is a block of data (reception completion data block) continuously received from the head. Judgment (Step H6)
If not, the process ends. If there is, the reception completion data block is taken out from the primary storage area of the communication data, and a data reception notification is sent to the communication control relay means 21 together with the connection identifier and the reception completion data block (step H7). After
The reception completion data block is deleted from the primary storage area of the reception data, and the data next to the reception completion data block in the primary storage area of the reception data is set as the head of the primary storage area of the reception data.

For example, of the data corresponding to the CID stored in the primary storage area of the received data, the reception completion data block of the 600-byte chunk of data continuously received from the first one is received. The data is notified from the primary storage area to the communication control relay means 21 together with the connection identifier CID and the reception completion data block, and the offset position 601 which is the next data of the reception completion data block is set to the head of the reception data primary storage area. Can be exemplified.

When the communication control relay means 21 is notified of the reception of the data including the connection identifier and the data from the error control means 22, the communication control relay means 21 reads the second connection identifier corresponding to the connection identifier CID from the storage means 25, and executes the communication protocol processing. It requests the means 24 to transfer data (reception completed data block) together with the second connection identifier. Upon receiving the data transfer request together with the second connection identifier, the communication protocol processing means 24 performs data transfer with the communication protocol processing means 32 in the server terminal device 3 (step H8).

Further, in the server terminal device 3, when the communication protocol processing means 32 receives the transfer data from the communication protocol processing means 24 (step I1), the communication protocol processing means 32 delivers the data to the communication service means 31 to notify the data ( Step I2) is performed.

In the communication terminal device 1, after the frame transmission by the physical interface control means 14 to the physical interface control means 23 (step G 4), the error control means 13
It is determined whether or not the received communication packet of the data A, data B, and data D is a successful reception packet (step G5). If the successful reception packet is received, it is stored as unconfirmed transmission packet information in the storage unit 15. The processing of packet contents deletion (step G6) is performed by erasing the contents of the communication packet, and then the processing is terminated. Regarding the communication packet of D, if the reception of the communication packet is not notified before the elapse of a predetermined time after the transmission of the communication packet, it is considered that the transmission of the communication packet has failed, and stored in the storage unit 15 again. Based on the frame error history of the wireless communication line 4 (the second optimum Packet length) is calculated, in order to initiate a retransmission processing of the communication data that failed to transmit, the process returns (step G7) to the previous packet created (step G2). Thereafter, retransmission is repeated in the same manner until transmission of all data is completed.

For example, assuming that the second optimum packet length is 100 bytes, 10
It is divided into three data of 0 byte each (data C1, data C2, and data C3 from the beginning, respectively), and [data C1, CID, 601], [data C2,
CID, 701] and [data C3, CID, 801], and requests the physical interface control means 14 to transmit these three communication packets. Is stored in the storage unit 15 as unconfirmed transmission packet information.

FIG. 5 is a flowchart showing a data communication operation from the server terminal device 3 to the communication terminal device 1 as a data communication operation process in the data communication system.

That is, in the case of this data communication operation, in the server terminal device 3, the communication service means 31 generates a data transmission request for requesting the communication protocol processing means 32 to transmit data together with the second connection identifier (step J1). Then, the communication protocol processing unit 32 performs data transfer (step J2) by transmitting data to and from the communication protocol processing unit 24 of the relay device 2.

Next, in the relay device 2, when the communication protocol processing means 24 receives the transfer data (step K1), it notifies the communication control relay means 21 of the second connection identifier and the data. The communication control relay means 21
Receiving the notification of the connection identifier and the data of
5, the connection identifier corresponding to the second connection identifier is read, and a request for transmitting a data transmission message including the connection identifier and the data is made to the error control means 22. Therefore,
When receiving the data transmission request including the connection identifier and the data, the error control unit 22 calculates the optimum packet length based on the frame reception history of the wireless communication line 4 stored in the storage unit 25, and converts the data into the optimum packet length. A packet composed of a connection identifier and offset information indicating the position of the divided transmission data from the beginning of the connection from the start of connection is generated for each of the divided transmission data, which is the divided data divided by the length To create a packet (step K
2), and requests the physical interface control means 23 to transmit a communication packet. Error control means 22
Performs the process of storing the packet contents (step K3) by storing the contents of the communication packet in the storage means 25 as unconfirmed transmission packet information. Further, upon receiving the request for transmission of the communication packet from the error control unit 22, the physical interface control unit 23 converts the communication packet into a frame and transmits the frame to the physical interface control unit 14 of the communication terminal device 1 (step K3). Is performed.

Further, in the communication terminal device 1, when the physical interface control means 14 receives a frame from the physical interface control means 23 of the relay device 2 (step L1), it checks whether or not the frame is received without error. , The size of the frame, the time it was received,
By storing information consisting of the result of the reception of the frame (successful reception or unsuccessful reception) as the frame reception history in the storage unit 15, the processing of the frame reception history storage (step L2) is performed. Notify the communication packet.

Thereafter, the error control means 13 determines whether or not the communication packet has been received without error (whether the communication packet has been successfully received or failed) (step L3). If the reception has failed, a reception failure notification packet including a connection identifier and offset information is created, and a request for transmission of a reception failure notification packet (step L9) is made to the physical interface control means 14, and the processing is terminated. If the communication packet has been successfully received, a reception success notification packet including the connection identifier and the offset information is created, and the physical interface control means 14
, Requesting transmission of a reception success notification packet (step L4), further storing the data of the communication packet together with the offset information in the primary storage area of the reception data corresponding to the connection identifier of the storage means 15, and setting the offset indicated by the offset information The process of storing the packet in the primary storage area by recording that the data of the data size is received from the value is performed (step L5).

At this time, of the data corresponding to the connection identifier stored in the primary storage area of the received data, it is determined whether or not there is a block of data continuously received from the head (reception completion data block). Judgment (Step L6)
If not, the process is terminated. If there is, the reception completion data block is taken out from the primary storage area of the communication data, and a data reception notification (step L7) is sent to the mobile terminal communication control means 12 together with the connection identifier and the reception completion data block. After that, the reception completion data block is deleted from the primary storage area of the reception data, and the data next to the reception completion data block in the primary storage area of the reception data is set as the head of the primary storage area of the reception data.

When the mobile terminal communication control means 12 receives the data reception notification including the connection identifier and the data from the error control means 13, the mobile terminal communication control means 12 additionally stores the data in the reception data storage area corresponding to the connection identifier in the data storage means 15. After the data is additionally stored (step L8), the process is terminated. or,
When receiving the data reception request from the communication service means 11, the mobile terminal communication control means 12 retrieves the data from the storage means 15 from the reception data storage area corresponding to the connection identifier included in the data reception request, and makes a data reception request. The data is transferred to the communication service unit 11, but the extracted data is deleted from the storage unit 15.

By the way, in the relay device 2, after the frame transmission by the physical interface control means 23 to the physical interface control means 14 of the communication terminal device 1 (step K3), the error control means 22 It is determined whether the received communication packet is a successfully received packet (step K5).
If the packet has been received successfully, the packet contents are deleted by deleting the contents of the communication packet stored as the unconfirmed transmission packet information in the storage means 25 (step K).
After performing the processing of 6), the processing is terminated, but the reception of the reception failure packet related to the communication packet is not received, or the reception of the communication packet reception success packet is not notified before a predetermined time has elapsed after the transmission of the communication packet. In this case, it is considered that the transmission of the communication packet has failed, and the optimum packet length (second optimum packet length) is calculated again based on the frame error history of the wireless communication line 4 stored in the storage unit 25 and transmitted. In order to start the retransmission processing of the communication data that failed in (1), the process returns (step K7) before packet creation (step K2). Thereafter, retransmission is repeated in the same manner until transmission of all data is completed.

In the above-described data communication system, the communication packet is retransmitted as error control of the communication packet between the communication terminal device 1 and the relay device 2. A correction code or the like can be used.

[0077]

As described above, according to the data communication method and the data communication system of the present invention, the line quality is estimated based on the packet error history on the radio line, and the packet size according to the line quality is estimated. Since the control is performed, the communication efficiency on the wireless line, which is a communication bottleneck, is improved. As a result, the communication efficiency can be controlled in accordance with the change in the communication quality of the wireless line, and the entire communication between the communication terminal apparatus and the server terminal apparatus can be controlled. Communication efficiency is improved. In addition, information necessary for protocol control is first reported from the communication terminal device to the relay device, and since the main protocol control is performed between the relay device and the server terminal device, data communication between the communication terminal device and the relay device is performed. The overhead of the control information for the protocol control for the communication is reduced, and as a result, the communication efficiency on the radio line, which is a communication bottleneck, is improved, and the communication efficiency between the communication terminal device and the server terminal device is greatly improved. Be able to contribute. Further, since the connection between the communication terminal device and the server terminal device is terminated at the relay device, the existing technology can be applied to the server terminal device side, and the configuration is not necessarily required to be changed. As a result, the interoperability of the server terminal device with the existing device is improved, and the cost reduction when applied to the existing data communication system can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a data communication system according to one embodiment to which a data communication method of the present invention is applied.

FIG. 2 is a flowchart showing a connection operation process in the data communication system shown in FIG.

FIG. 3 is a flowchart showing a disconnection operation process in the data communication system shown in FIG. 1;

FIG. 4 is a flowchart illustrating a data communication operation from a communication terminal device to a server terminal device as a data communication operation process in the data communication system illustrated in FIG. 1;

FIG. 5 is a flowchart showing a data communication operation from the server terminal device to the communication terminal device as a data communication operation process in the data communication system shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Communication terminal device 2 Relay device 3 Server terminal device 4 Wireless communication line 5 Wired communication network 11, 31 Communication service means 12 Mobile terminal communication control means 13, 22 Error control means 14, 23 Physical interface control means 15, 25 Storage means 21 communication control relay means 24, 32 protocol processing means

Claims (7)

[Claims] 1. A data communication method for performing data communication between a communication terminal device and a server terminal device connected to a relay device by a wireless line and a wired line network, respectively, comprising: A first communication data error control step of performing communication data error control between the relay devices via the wireless line; and a communication data error control between the relay device and the server terminal device via the wired network. And a second data communication error control for performing a data communication error control. 2. A data communication method for performing data communication between a communication terminal device and a server terminal device connected to a relay device by a wireless line and a wired line network, respectively, wherein the communication terminal device comprises: Transmitting the communication data to the relay device, and when the relay device succeeds in receiving the communication data from the communication terminal device, transmits a reception success notification to the communication terminal device; If the reception success notification is not received before a lapse of time, the communication data is retransmitted to the relay device, whereby error control of communication data is performed between the communication terminal device and the relay device via the wireless line. Performing a first communication data error control, performing a second data communication error control between the relay device and the server terminal device via the wired network, Data communication method characterized in that at least performed. 3. A data communication method for performing data communication between a communication terminal device and a server terminal device connected to a relay device by a wireless line and a wired line network, respectively, wherein the relay device and the relay device A first data communication error control for performing error control of communication data between the server terminal devices via the wired network is performed, and the relay device transmits the communication data transmitted from the server terminal device to the communication terminal device. Transmitting, if the communication terminal device succeeds in receiving the communication data, the communication terminal device transmits a reception success notification to the relay device, and the relay device did not receive the reception success notification before a predetermined time has elapsed. In this case, by retransmitting the communication data to the communication terminal device, a second communication data for performing error control of communication data between the communication terminal device and the relay device via the wireless line. Data communication method characterized in that at least perform the data error control. 4. A relay device connected to a server terminal device via a wired network and connected to a communication terminal device via a wireless channel, wherein an error in communication data with the communication terminal device via the wireless channel. Performing at least a first communication data error control step of performing control, and a second data communication error control of performing communication data error control with the server terminal device via the wired network. Relay device. 5. A relay device connected to a server terminal device by a wired network and connected to a communication terminal device by a wireless line, wherein the relay device receives communication data from the communication terminal device and communicates from the communication terminal device. If the data is successfully received, a reception success notification is transmitted to the communication terminal device, and if the reception success notification is not received before a predetermined time elapses from the communication terminal device, the data is retransmitted from the communication terminal device. By receiving communication data, performing first communication data error control for performing error control of communication data with the communication terminal device via the wireless line, and performing the wired line communication with the server terminal device A relay apparatus for performing at least second data communication error control for performing error control of communication data via a network. 6. A relay device connected to a server terminal device via a wired network and connected to a communication terminal device via a wireless network, wherein the relay device communicates communication data with the server terminal device via the wired network. Performing first data communication error control for performing error control, transmitting communication data transmitted from the server terminal device to the communication terminal device, and receiving a reception success notification transmitted when the communication data is successfully received. If the communication data is not received from the communication terminal device before a predetermined time has elapsed, the communication data is retransmitted to the communication terminal device, so that the communication data is transmitted between the communication terminal device and the relay device via the wireless line. A relay device for performing at least second communication data error control for performing error control. 7. The relay device and the first communication terminal device are connected by a wireless line, and the relay device and the second communication terminal device are connected by a wired network. In a data communication system for performing error control of data communication by packet transfer between a communication terminal device and the second communication terminal device, the first communication terminal device controls connection between the communication terminal devices with respect to a higher-level protocol. First transport layer communication control means for providing data and an interface for data communication, and transmission and reception of a first communication packet with communication error control between the relay apparatus and the fourth transport layer communication control means.
And transmitting the first communication packet passed from the first transport layer communication control means to the relay device, and transmitting the fourth communication packet received from the relay device. First error control communication means for passing to the first transport layer communication control means, wherein the second communication terminal device performs connection control data and data communication between the communication terminal devices with respect to an upper layer protocol. And a second transport layer communication control means for providing a second communication packet and a third communication packet with a communication error control between the relay device and the second transport layer communication control means. The second communication packet transmitted from the second transport layer communication control means is transmitted to the relay device, and the second communication packet received from the relay device is transmitted to the second traffic packet. 4 to pass to Sport layer communication control means
Error control communication means, wherein the relay device is configured to perform communication error control with the first communication terminal device.
A second error control communication means for receiving the communication packet and transmitting the fourth communication packet, and transmitting and receiving the second communication packet with communication error control between the second communication terminal device and the second communication terminal device. Third error control communication means for receiving the third communication packet, converting the first communication packet into the second communication packet, and converting the third communication packet into the fourth communication packet And a conversion means for converting the data into a data communication system.