JPS63299420A - Picture data transmission system - Google Patents

Abstract

PURPOSE:To improve transmission efficiency, by dividing a data text into plural blocks, adding and sending an error detection code on every block, designating the block in which an error is detected, and sending again only the block in which the error is generated. CONSTITUTION:It is assumed that a transmission text is divided into, for example, 32 blocks. And it is sent after the identification number of the block and the error detecting code (BCC) are attached on every block. A reception side checks a transmission/reception text at every block, and when the error is detected, returns the list of the identification number of the block. A transmission side recovers the error by sending a re-transmission text consisting of only a data block in which the error is generated. Hereafter, the above re- transmission procedure is repeated until a text without the error is received. Thus, by re-sending only the data block in which the error is generated, it is possible to perform the transmission of picture data with superior efficiency.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the transmission of image data, and particularly relates to a retransmission method in the event of an error [Prior Art] Traditionally, as a method of transmitting image data, There are basic data transmission methods and methods using HDLC procedures. These methods are based on JTSC6362 and JI
It has been developed as a standard model S-C636B and is a well-known technology.

[The problem that the invention attempts to solve]

According to these methods, since an error detection code is added to each unit of transmitted text I, there is a drawback that if even a single error occurs in the text, the entire text I must be retransmitted.

In addition, since it is necessary to set the error occurrence probability within the child kiss 1 to less than 1, the text length cannot be increased, resulting in a reduction in transmission efficiency, which is solved by the present invention. In other words, the object of the present invention is to provide an image data transmission system that improves the above-mentioned drawbacks by detecting transmission errors and retransmitting each block of text I- into a plurality of blocks. It's about doing.

[Means for Solving the Problem] The image data transmission method of the present invention is an image data transmission method in which image data is transmitted by binding one or more cheetah texts 1 to 1 to 1 in a plurality of flocks. If an error is detected when one data text is sent, the block in which the error occurred is indicated, and the error detection code is sent to each block. [Embodiment] Next, the present invention will be explained with reference to the drawings. Fig. 1 is a block diagram showing a first embodiment of the present invention. In the figure, image data generated by an image generator 1 is modulated by a modem 2T, and sent from an NCU (network control unit) 3T to a public telephone line 11. On the receiving side, it is demodulated by a modem 2R via an NCU 3R. The image is received by the image generating device 5.

Figure 2 is an explanatory diagram showing the transmission text I to format I used for the above data transmission. In the figure, the transmission text is assumed to be divided into 32 blocks, and each block is divided into blocks. A recognition number and an error detection code (BCC) are added and sent.The receiving side checks the received text block by block, and if an error is detected, it recognizes the block and sends back the list 1~ of the identification number. The figure is an explanatory diagram without showing the format of the recognition number list of the block in which an error has been detected.
FIG. 4 is an explanatory diagram showing the format of the text retransmitted by the transmitting side in response to the above negative response, which indicates that an error has occurred in blocks j and k. On the transmitting side, the error is recovered by sending a retransmission text I consisting only of the data block 1 in which the error occurred.
The above retransmission procedure is repeated until an error-free text is received. FIG. 5 is an explanatory diagram showing an outline of the above-mentioned transmission. FIG. 6 is a transmission text formatter according to a second embodiment of the present invention. The transmission text 1- is divided into 32 blocks as in the first embodiment, or the block identification number is not sent.3 When the receiving side detects an error, it reads the serial number of the block. The format of the returned data is exactly the same as that shown in FIG. 3 above.7 FIG. 7 is an explanatory diagram showing the format of the text reproduced by the sending side in response to the above negative response. On the sending side, the retransmission text consisting of only the 1st, jth, and 2nd blocks in which the error occurred is sent, and the block identification number is not sent. In the second embodiment, blocks are recognized by managing block serial numbers on both the transmitting side and the receiving side.

Furthermore, if the block length is determined so that the probability of error occurrence within a block is less than 1, there is no need to limit the text length.

〔Effect of the invention〕

As explained above, efficient image data transmission is achieved by dividing one transmitted text 1~ into multiple blocks, adding an error detection code to each block, and retransmitting only the data block with an error. It becomes possible.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a first embodiment of the image data transmission method according to the present invention, Fig. 2 is an explanatory diagram showing the format of the transmission text, and Fig. 3 shows the cheater format of a negative response. FIG. 4 is an explanatory diagram showing the formatting and sorting of the retransmission text; FIG. 5 is an explanatory diagram showing the outline of the transmission procedure; FIG. 6 is an explanatory diagram showing the format of the transmission text of the second embodiment; FIG. 7 is an explanatory diagram showing the format of retransmission text in the second embodiment. 1... Image generator, 2T, 2R... Motem, 3T
3R...Network control device, 4...Public telephone line, 5...
Painting (Hayako de Bluest) Memi 〒 -1～-11

Claims (4)

[Claims] (1) In an image data transmission method in which image data is transmitted as one or more data texts, the data text is divided into a plurality of blocks, and an error detection code is added to each block and transmitted, An image data transmission method characterized in that when an error is detected when transmitting the data text, a block in which the error occurred is indicated, and only the block in which the error occurred is transmitted again. (2) When a data text is divided into multiple blocks, a recognition code is added to identify each block, and if an error is detected when transmitting the data text, the block in which the error occurred is identified by the recognition code. An image data transmission system according to claim 1, which is specified by: (3) When transmitting a data text divided into multiple blocks, the blocks are counted sequentially, and if an error is detected when transmitting the data text, the block containing the error is counted according to the counted value. An image data transmission method according to claim 1 or 2. (4) Image data according to claim 1, 2, or 3, wherein the block length of each of a plurality of blocks is determined so that the bit error probability is less than 1. Transmission method.