JPH04253433A - Data retransmission system - Google Patents

Abstract

PURPOSE:To reduce the reduction of transmission efficiency by adding only the error detection code to a communication data and transmitting an error correction code as a retransmitting data in the case of retransmission caused by error. CONSTITUTION:The transmitting data is transmitted through a switching part 31 to an error detection code addition part 30 and transmitted to the equipment of a communicating party after calculating the error detection code and adding an error detection code 102. At such a time, an error correction code preparation and storage part 34 prepares and stores the error correction code in respect to the information of an information part 101. When retransmission is requested from a communication control part 2, a header preparation part 33 adds a header part 200 to the data of the error correction code 201 stored in the error correction code preparation and storage part 34 and transmits the data through the switching part 31 to the error detection code addition part 30. At this part 30, an CRC 202 is added to the data and it is transmitted to the equipment of the communicating party.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a data retransmission system,
In particular, the present invention relates to a data retransmission method for retransmitting data when an error occurs in data communication.

0002

[Prior Art] Conventionally, in a data retransmission system in this type of data communication, a device that receives data determines whether or not there is an error in the received data using an error detection code added to the received data. If this is detected, a retransmission request is made to the data transmitting device, and the data transmitting device retransmits the data that has received the retransmission request.

0003

[Problems to be Solved by the Invention] The conventional data retransmission method described above retransmits all frame data if there is an error in even one bit in the received data frame. This has the disadvantage that data transmission efficiency decreases when this occurs.

0004

[Means for Solving the Problems] The data retransmission system of the present invention is composed of a data receiving section, a data transmitting section, and a communication control section that controls data communication, and the data receiving section transmits a received frame header section. a frame identification unit that identifies the received data frame; an error detection unit that detects errors in the received data frame;
a frame storage unit that temporarily stores the received data frame; an error correction frame storage unit that temporarily stores the error correction frame received as retransmission data; and a frame storage unit that performs error correction on the received data frame to create a normal data frame. an error correction unit for reproducing; a first switching unit for switching between the received data frame from the frame storage unit and the normal data frame from the error correction unit; and a reception unit for receiving data; The data transmitting unit includes a transmitting unit that transmits data, a first header creating unit that adds a header to the transmitted data, and an error correction code creation and storage unit that creates and stores an error correction code for the transmitted data. , a second header creation unit that creates a header for the error correction frame; a second switching unit that switches transmission frames from the first and second header creation units; and a transmission frame from the second switching unit. and an error detection code adding section that adds an error detection code to the communication data, and normally only the error detection code is added to the communication data, and when retransmission is due to an error, the error correction code is sent as retransmission data. do.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the data retransmission system of the present invention.

The data communication device of this embodiment is constructed by connecting a communication control section 3 between a data reception section 1 and a data transmission section 2. The data reception unit 1 includes a frame identification unit 10 that identifies the header part of a received frame, an error detection unit 11 that detects errors in the received frame, a frame storage unit 12 that temporarily stores the received data frame, and an error detection unit 11 that detects errors in the received frame. Error correction frame storage unit 1 that temporarily stores corrected frames
3, an error correction unit 14 that corrects errors in received data frames and reproduces normal data frames, a switching unit 15 that switches received frames, and a reception unit 16 that receives data. The unit 3 includes a transmitting unit 35 that transmits data, a header creating unit 32 that adds a header to the transmitted data, and an error correction code creation and storage unit 3 that creates and stores error correction codes for the transmitted data.
4, a header creation section 33 that creates a header for an error correction frame, a switching section 31 that selects a transmission frame, and an error detection code addition section 30 that adds an error detection code to the transmission frame. The communication control section 3 controls the data reception section 1 and the data transmission section 3.

FIG. 2 is a diagram showing an example of the frame format of the data frame in FIG. (hereinafter referred to as DATA) 101 and an error detection code (hereinafter referred to as CRC) 102 for detecting errors in this frame.

FIG. 3 is a diagram showing an example of the frame format of the error correction frame in FIG. 1, which has an error correction code for the data frame in FIG. Header section (hereinafter referred to as Hc) 200 indicating that it is an error correction frame
, an error correction code (hereinafter referred to as FEC) 201 for the DATA 101 in FIG. 2, and a CRC 202 for detecting errors in this frame.

Next, the operation of this embodiment will be explained.

When the frame identification section 10 receives the data frame shown in FIG. 2, it identifies that the header section of the frame is Hd100, and the frame is considered to be a data frame. At this time, the received data is transferred to the frame storage section 12. At the same time, the error detection unit 11 calculates an error detection code for the received data, and sends the result to the CRC 102 in FIG.
It is determined whether there is an error by comparing the
Notify.

If there is no error, the frame storage unit 12
The received data stored in is sent to the receiving section 16 via the switching section 15. If there is an error, the received data remains stored in the frame storage section 12, and a retransmission request is made to the communication control section 2 due to the error.
A retransmission request message is sent from the data transmitter 3. Since the other party's device now transmits the error correction frame shown in FIG. 3, the data receiving section 1 receives this.

When the error correction frame shown in FIG. 3 is received, the frame identification section 10 in the data reception section 1 identifies the header section and, if determined to be Hc200, stores the received data in the error correction frame storage section 13. At the same time, the error detection unit 11 calculates an error detection code for the received data, and compares the result with the CRC 202 of FIG. 3 to determine whether there is an error. If there is no error, the process moves to the next operation.

[0014] The error correction unit 14 first reads the frame storage unit 12.
By performing error correction from the DATA 101 stored in the error correction frame storage section 13 and the FEC 201 stored in the error correction frame storage section 13, the DATA 101 containing an error is regenerated into normal data. The reproduced received data is sent to the receiving section 16 via the switching section 15.

[0015] If an error is detected in the received error correction frame, the error detection unit 11 notifies the reception unit 16, requests the communication control unit 2 to retransmit the error, and transmits the data. A retransmission request message is sent from part 3.

Next, the operation of the data transmitter 3 will be explained.

DATA10 of the data frame shown in FIG.
0 is sent from the transmitter 35. Hd100 is added by the header creation unit 32 to indicate that it is a data frame. The transmission data is sent via the switching unit 31 to the error detection code addition unit 30, which calculates the error detection code and adds the CRC.
102 is added and sent to the other party's device. At this time, the error correction code creation/storage unit 34 creates and stores error correction codes for the information of the DATA 101.

When there is a retransmission request from the communication control section 2, the header generation section 33 sends the error correction code generation and storage section 34 to the error correction code generation and storage section 34.
Hc2 for the FEC201 data stored in
00 is added and sent to the error detection code adding section 30 via the switching section 31, where a CRC 202 is added and sent to the partner device.

[0019]

Effects of the Invention As explained above, the present invention adds an error detection code to a data frame when performing data communication, and when an error is detected on the receiving side, the code is created and saved in advance on the transmitting side. Only the error correction code for the previously sent data is sent as retransmission data, and the receiving side performs error correction on the received data that had an error when receiving the error correction code. It is sufficient to send only the error correction code with a short data length as retransmission data. Therefore, it has the effect of reducing the decrease in data transmission efficiency when there is an error in the communication line.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a data retransmission system of the present invention.

FIG. 2 is a diagram showing an example of a frame format of a data frame in FIG. 1;

FIG. 3 is a diagram showing an example of a frame format of an error correction frame in FIG. 1;

[Explanation of symbols]

1 Data receiving section 2 Communication control section 3 Data transmitting section 10 Frame identifying section 11 Error detecting section 12 Frame accumulating section 13 Error correcting frame accumulating section 14 Error correcting section 14, 31 Switching section 16 Receiving section 30 Error detection code adding section 32, 33 Header creation section 34 Error correction code creation and storage section 35 Transmission section

Claims (1)

[Claims] 1. The data receiving section includes a data receiving section, a data transmitting section, and a communication control section that controls data communication, and the data receiving section includes a frame identifying section that identifies a received frame header section, and a frame identifying section that identifies a received frame header section. an error detection section that performs error detection, a frame storage section that temporarily stores the received data frame, an error correction frame storage section that temporarily stores the error correction frame received as retransmission data, and an error correction frame storage section that temporarily stores the received data frame. an error correction unit that performs error correction and reproduces a normal data frame; a first switching unit that switches between the received data frame from the frame storage unit and the normal data frame from the error correction unit; and a first switching unit that receives data. The data transmitter includes a transmitter that transmits data, a first header creator that adds a header to the transmit data, and a first header creator that creates an error correction code for the transmit data. an error correction code creation/storage unit for accumulating; a second header creation unit for creating a header for the error correction frame; a second switching unit for switching transmission frames from the first and second header creation units; and an error detection code adding section that adds an error detection code to the transmission frame from the second switching section.Normally, only the error detection code is added to communication data, and when retransmission due to an error, the error correction code is added. A data retransmission method characterized by sending data as retransmission data.